GIFT  OF 
Bureau    of    Railway   Economics 


•  HANDBOOK 


OF 


KAILROAD  CONSTRUCTION-; 


FOR   THE   USE   OF 


AMERICAN    ENGINEERS. 


CONTAINING   THE 


NECESSARY  RULES,  TABLES,  AND   FORMULA 


FOR  THE 


LOCATION,  CONSTRUCTION,  EQUIPMENT,  AND  MANAGEMENT  OF 
RAILROADS,  AS  £UILT  IN  THE  UNITED  STATES. 


15-8  Ellusttatlons 


BY 

GEORGE     L.     V  0  S  E  , 

CIVIL    ENGINEER. 


"  RULES     THEMSELVES     OBLIGE     US     TO    REFLECT,     THAT     WE     MAY    SEE    WHETHER    WE    HAVE     NOT 
DEPARTED     FROM    THEM."  —  NAPOLEOX. 


BOSTON  AND  CAMBRIDGE  : 
JAMES    MUNROE    AND    COMPANY. 

1857. 


P-,  -3LIG  LIBRARY 

DUPLICATE 


ft 


Entered  according  to  Act  of  Congress,  in  the  year  1857,  by 

JAMES   MUNROE    AND    COMPANY, 
In  the  Clerk's  Office  of  the  District  Court  of  the  District  of  Massachusetts. 


CAMBRIDGE  : 
ALLEX      AND      FARNHAM,      PRINTERS. 


PREFACE. 


THE  object  of  this  work  is  to  give  in  the  plainest  possible 
manner  all  instructions,  rules,  and  tables  necessary  for  the 
location,  construction,  equipment,  and  management  of 
railroads. 

As  a  general  thing,  American  engineers  are  not  educated 
for  their  business ;  and  when  they  do  possess  a  knowledge 
of  pure  science,  they  are  at  a  loss  how  to  apply  it. 

The  reader  is  presumed  acquainted  with  the  elements  of 
arithmetic,  geometry,  algebra,  and  mechanics ;  being  thus 
provided,  he  will,  by  a  perusal  of  what  follows,  be  enabled 
to  correctly  proportion  bridges,  of  wood,  stone,  and  iron : 
abutments,  piers,  retaining  walls,  superstructure,  and  loco 
motive  engines;  and'  to  plan  and  lay  out,  execute,  and 
estimate  any  description  of  work  occurring  upon  railroads. 

As  the  object  has  been  more  to  be  useful  than  original. 
the  best  engineering  writers  and  experimenters  have  been 
consulted;  among  whom  are, —  Gauthey,  Navier,  Vicat, 


817038 


IV  PREFACE. 

Tredgold,  Barlow,  Totten,  Fairbairn,  Hodgkinson,  Clark, 
and  Lardner.  Also  a  great  number  of  reports  by  American 
civil  engineers  upon  railroad  matters. 

If  assumptions  take  the  place  of  demonstration,  it  will 
be  on  good  authority.  Readers  will  bear  in  mind  that  the 
work  is  a  "  handbook,"  and  not  a  "  treatise."  It  is  intended 
more  as  an  office  companion  than  as  a  text-book  for  stu 
dents.  It  will  give  in  all  cases  the  actual  numerical  result 
needed,  whether  it  be  the  scantling  of  a  bridge  chord,  the 
thickness  of  a  wall,  or  the  dimensions  of  a  locomotive 
boiler. 

In  connection,  it  will  be  found  convenient  to  use  the 
works  of  Trautwine  and  Henck,  on  Field  Work ;  of  Lieu 
tenant  Smith,  on  Topography;  Davies,  on  Surveying;  and 
Gurley,  on  the  Use  of  Instruments. 

Any  one  wishing  a  complete  treatise  on  the  principles  of 
bridge  construction  is  referred  to  the  excellent  work  of 
Hermann  Haupt. 

I  take  this  opportunity  of  heartily  thanking  the  engineers 
who  in  many  ways  have  aided  in  making  the  work,  as  it  is 
believed,  of  some  worth. 

G.  L.  V. 


GENERAL  TABLE  OF  CONTENTS, 


PAGE 

INTRODUCTION, 1 

CHAPTER  I.  — RECONNOISANCE 12 

II.  —  SURVEY 24 

III.  —  LOCATION   .        .        .        .        .        .        .        .41 

IV.  —  PRELIMINARY  OPERATIONS            ...  55 
V.  —  LAYING  OUT  WORK           .        .        .        .        .89 

VI.  —  EARTHWORK 97 

VII.  —  ROCKWORK 115 

VIII.  —  WOODEN  BRIDGING 122 

IX.  —  IRON  BRIDGING 192 

X. —  STONE  BRIDGING            .....  233 

XL  — MASONRY 248 

XII.  —  FOUNDATIONS 261 

XIII.  —  SUPERSTRUCTURE 272 

XIV.  — EQUIPMENT 302 

XV.  —  STATIONS 403 

XVI.  —  MANAGEMENT 413 

• 

APPENDIX 459 


ANALYTICAL   INDEX. 


INTRODUCTION. 

PAGE 
Rise  and  progress  of  railroads      ....  1 

Influence  of  railroads  .  ...  3 

Safety  of  railroad  travelling         .  .5 

Preliminary  operations  ......  5 

Mechanical  principles  of  locomotion         .  .  .  6 

Determination  of  character  of  road  ...  7 

Gauge       .  .  .  8 

General  establishment  of  route          .  .  .  .  .10 


CHAPTER    I. 

RECONNOISSANCE, 

General  topography         .  .  .  •  •  •  12 

Barometrical  levelling  .  .  .  »  .  .18 

CHAPTER    II. 

SURVEY. 

Topographical  sketching  •               24 

General  establishment  of  grades  .                           ...         82 

Equating  for  grades         .             .  34 

Comparison  of  surveyed  lines  •         39 


Vlll 


ANALYTICAL   INDEX. 


CHAPTER     III 

LOCATION. 


Alignment  .. 

Final  adjustment  of  grades 
Comparison  of  located  lines 


41 


47 


CHAPTER    IV. 

PRELIMINARY    OPERATIONS. 


Specification  . 

Contract  . 

Solicit  .  . 

Bid  .. 

Comparison  of  bids    . 


55 

82 
84 
86 
87 


Slopes 
Culverts 
Masonry 
Tunnels 


CHAPTER     V. 

LAYING   OUT    WORK. 


89 
90 
91 
95 


CHAPTER     VI 

EARTHWORK. 

Form  of  railroad  sections  .  .  . 

Excavation  and  embankment  .  . 

Transport  of  material       .  .  .  . 

Average  haul  .  .  .  . 

Drainage  ..... 

Method  of  conducting  construction  operations 


93 
104 
106 
106 
109 
111 


ANALYTICAL   INDEX.  IX 


CHAPTER    VII. 

KOCKWORK. 

Rock  excavation  .  .  .  .  .  115 

Blasting  and  quarrying          .  .  .  115-117 

Tunnelling  .  .  .  .  •  •  •  118 


CHAPTER    VIII. 

WOODEN    BRIDGING. 

Of  the  forces  at  work  in  bridges  122 

Extension       .                                                                •  .123 

Compression         ......  123 

Cross  strain    ...*-*  .124 

Detrusion              ...                          .  '  126 

Strength  of  materials             ...  .126 

Rules  for  practice             ...  131 

Of  the  truss .139 

Of  the  arch          ...  169 

Of  the  road-way        .....  .174 

Lateral  bracing    .....  175 

Pile  bridging               ....  .178 

Trestling               ....  180 

Draw  bridges             .                                      .  .181 

Centres  182 


CHAPTER  IX. 

IRON    BRIDGES. 

Nature  and  strength  of  iron               .  .                          •             .192 

Classification  of  iron  bridges       .  .             .             194 

Iron  truss  frames        ...  .                     202 

Suspension  bridges           .  203 

Boiler  plate  bridges  .             .  •       223 


ANALYTICAL   INDEX. 


CHAPTER    X. 

STONE    BRIDGING. 

Of  the  water-way  .  .  .  .  .  *          .  233 

Form  of  the  arch       .......  236 

Thickness  of  voussoirs     .  .  .  .  .  .    .  238 

Form  and  thickness  of  abutments     .....  239 

Form  and  dimensions  of  piers     .....  245 


CHAPTER    XI. 

MAS  ONE  Y. 

Stone                                                     ...  .248 

Cements,  mortars,  and  concretes             ....  249 

Construction  of  arches,  wings,  and  parapet                            .  .253 

Culverts  and  drains          ......  255 

Retaining  walls          .             .             .             .             .             .  .256 


CHAPTER  XII. 

FOUNDATIONS, 

Pile  driving,  common  system       .             .  .             .   v                      262 

Mitchell's  screw  pile .            .  .                                            266 

Potts's  atmospheric  system            .             .  ,            .             .             266 

Coffer-dam     .             .             .             .  .             .             .             .267 

Caisson  269 


CHAPTER    XIII. 

SUPERSTRUCTURE. 

Timber  work  .  .  .  .  .  .  .273 

Rail  section  276 


ANALYTICAL   INDEX.  XI 

Chairs  and  joints       .             .             .             •  •             •             .282 

Frogs        .             .  290 

Switches         .....  •       294 

Sidings  and  crossings       .  •                          298 
Tracklaying  .....•••       298 

Elevation  of  exterior  rail            .            .            •  •            •            298 


CHAPTER    XIV. 

EQUIPMENT. 

PART  I.       LOCOMOTIVES. 

Introduction  ...  ....       302 

Birth  and  growth  of  the  locomotive         ....  302 

The  English  locomotive  of  1850                     .             .  .       304 

The  American  locomotive  of  1855           .             .  305 

General  description  .                          .  .306 

Mechanical  and  physical  principles  312 

Resistance  to  the  motion  of  trains    .             .             .  .             .312 

Traction  and  adhesion     .             .             .             .  •             316 

Fuel  .  .317 

Generation  of  steam        ....  330 

Application  of  steam              .                          .  .336 

Boiler  proportions  and  dimensions            .             .  .             340 

Rules  and  tables  for  practice                                       .  .354 

Adaptation  of  locomotives  to  the  movement  of  trains  .                          360 

Classification  of  engines        .             .             .             .  .             .371 


PART  SECOND. 
CARS. 

Wheels  and  axles  .  .  .  •  •  .  396 

Classification  of  cars  .  •  400 

Retarding  of  trains  .  •  401 


Xll  ANALYTICAL   INDEX. 

CHAPTER    XV. 

STATIONS. 

Classification  of  buildings      .             .             .             .             .             .  403 

Location  of  buildings       ......  403 

Terminal  passenger  house     .          4 .             .             .            .             .  403 

Terminal  freight  house    ......  405 

Way  passenger  and  freight  house      .  .  .  .  .407 

Engine  house  and  appurtenances             ....  405 

Wood  shed  and  tank             ......  405 

CHAPTEE    XVI. 

MANAGEMENT. 

Organization  of  employees           .             .             .             .             .  413 

Duties  of  employees  .  .  .  .  .  .415 

Number  of  trains  to  be  used        .             .             .             .             .  413 

Amount  of  service  of  engines  .  .  .  .  .418 

Expenses,  receipts,  profits            .             .             .             .             .  420 

Express  trains  .  .  .  .  .  .  .428 

Comparative  cost  of  working  heavy  and  light  trains       .             .  434 

Branch  roads              .......  436 

Reproduction  of  road  and  of  stock         .             .             .             .  437 

Working  railroads  by  contract         .....  439 

Classification  of  freight    .             .             .             .             .             .  439 

Time  tables    ........  443 

Locomotive  registers         ......  444 

Electric  telegraph     .......  454 

New  York  and  Erie  Railroad      .             .             .  456 


ANALYTICAL   IXDEX.  xiii 


APPENDIX. 

A. —  Decimal  Arithmetic      ........         459 

B.  —  Algebraic  formulae     .        .        .        .        .        .        .         .        .461 

C.  —  Weights  and  measures          .  .        .        .        .        .        464 

D.  —  Value  of  the  Birmingham  gauges    ......    465 

E.  —  Locomotive  boilers 466 

F. —  Effect  of  grades  on  the  cost  of  working 468 

G.  —  Form  for  a  locomotive  specification      .         .        .        .        .        471 
H.  —  Relative  cost  of  transport  by  railroad  and  by  stage  .        .        .476 
I.  —  Form  for  experimental  trips  with  locomotives       .        .        .        478 
K.  —  Proper  weight  for  locomotives 479 


• 


ADDITIONS,  ALTERATIONS,  AND  CORRECTIONS. 


The  reader  is  particularly  requested  to  apply  the  following  errata  before  perusing 
the  work.  They  are  partly  mistakes  in  printing,  and  partly  errors  in  the  original 
MS.  The  only  excuse  the  writer  can  offer  for  the  number  is,  that,  being  engaged  in 
Missouri,  while  his  publishers  were  in  Boston,  he  has  been  prevented  from  seeing  a 
single  proof-sheet  in  time  for  its  correction. 

Page  5,  line  7,  for  "499.999,"  read  "  499,999." 

—  5, 1.  9,  for  "49.999,"  read  "49,999." 

—  10, 1.  1,  for  "  can  be,"  read  "  can  never  be." 

—  12  to  23,  headings,  for  "reconnoitre,"  read  "reconnoissance." 

—  18, 1.  24,  for  "  36.9,"  read  "36.8." 

—  19, 1.  6,  for  "  table  B,"  read  "  table  D." 

—  24, 1.  1,  for  "  any  thing,"  read  "  every  thing." 

—  25, 1.  17,  for  "  horizontal  line  m  m  m,"  read  "  line  1,  2,  3,"  etc. 

—  26, 1.  2,  for  "  land,"  read  "  level." 

—  27, 1.  1,  for  "at  the  place,"  read  "  at  the  right  place." 

—  28, 1.  29,  "  for  "  reconnoitre,"  read  "  reconnoissance." 

—  30, 1.  3,  for  "  A  c  d  B,"  read  "  A  C  D  B." 

—  32, 1.  2,  the  point  m  in  the  cut/is  one  whole  division  above  C;  it  should  be  only 

three  fourths  of  a  division. 

—  38, 1.  10  from  bottom,  for  "  276,"  read  "  268." 

—  39,1.  10  from  bottom,  for  "  142.13,"  read  "143.13  ";  and  last  line,  for  "58.46," 

read  "  48.46," 

—  40, 1.  7,  for  "  10,310,667,"  read  "  10,277,333." 

—  42, 1.  9,  for  "  Thus,"  read  "  These." 

—  43, 1.  8  from  bottom,  for  "  2°.81  or  2°  4S/.6  "  read  "  2°.86  or  2°.61.6." 

—  "  1.  27,  for  "  Hencke,"  read  "  Henck." 

—  47,  48,  49,  for  "  McCullum,"  read  "  McCallum." 


Xvi  ADDITIONS,   ALTERATIONS,   ETC. 

Page  47, 1.  18,  for  " distance,"  read  "resistance." 

—  48, 1.  6,  for  "  infringing,"  read  "  impinging  " ;  line  9,  for  "  slacking,"  read  "  shack 

ling  " ;  1.  8  from  bottom,  for  "  increased,"  read  "  increafes." 

—  50,  1.  17,  for  "  110  +  15.60,"  read  "  110  -f  15.62." 

—  62, 1.  15,  for  "  45.59,"  read  "  45.49  " ;  also  1.  17,  for  "  1132,"  read  "  11.32." 

—  58, 1.  10,  for  "  of  size,"  read  "  and  size." 

—  "1.5  from  bottom,  for  "  one  cent,"  read  "  ^^  of  a  cent." 

—  61, 1.  3,  for  "  are  necessary,"  read  "  are  not  necessary." 

—  63, 1.  28,  for  "  stretches,"  read  "  stretchers." 

—  65, 1.  15,  for  "  spanded,"  read  "  spandrel." 

—  71, 1.  6  from  bottom,  for  "  left,"  read  "  let." 

—  73, 1.  19,  for  "  chains,"  read  "  chairs." 

—  74, 1.  5,  for  "  across  ties,"  read  "  on  cross-ties." 
-^  "  1.  12,  for  "  28  inches,"  read  "  27  inches." 

—  75, 1.  18,  for  "  land,"  read  "  haul." 

—  76,1.8,  for  "top,"  read  "bottom,"  and  for  "charred  when,"  read  "charred 

where." 

—  "  1.  11,  for  "  twopenny,"  read  "  tenpenny." 

—  78, 1.  1  and  2,  for  "base,"  read  "basis." 

—  84, 1.  13,  for  "  as,"  read  "  or." 

—  89, 1.  6,  for  "  whenever,"  read  "  wherever  " ;  1. 12,  for  "  Letting,"  read  "  Setting." 

—  90, 1.  4,  for  "  cost,"  read  "  cut." 

—  93, 1.  6,  for  "  37  and  38,"  read  "  36  and  37." 

—  95, 1.  1,  for  "  beach,"  read  "  bench" ;  1.  3,  for  "  to  so,"  read  "  so  to  " ;  1.  13,  for 

"b  being  10  ft.  back  of  2  is  ....  100.00,"  read  "b  being  10  ft.  back  of  2  is 
0.1  ft.  higher  than  2,  or 100.10." 

—  102, 1.  1,  head  of  middle  col.,  for  "  slopes  1£,"  read  "  slopes  1*." 

—  103, 1.  4  from  bottom,  for  "  and  ten  feet,"  read  "  and  one  end  ten  feet." 

—  104, 1.  9,  for  "  any,"  read  "  very."- 

—  108, 1.  9,  for  "  Elwood,"  read  "  Ellwood." 

—  115, 1.  5,  for  "  a  loam,"  read  "  a  berm  " ;  1. 16,  for  "  a  rent,"  read  "  a  vent." 

—  117, 1.  7,  for  "  volcanic,"  read  "  voltaic." 

—  "    1.  9,  for  "  Round  Drum,"  read  "  Round  Down." 

—  "    1.  18,  for  "  Col.  Puseling,"  read  "  Col.  Pasley." 

—  118, 1.  2,  for  "  Maillefaut,"  read  "  Maillefert." 

—  "    1.  16,  for  "insert,"  read  "invert." 

—  "    1.  25,  for  "quointed,"  read  "grouted." 

—  119, 1.  30,  for  "  furnished,"  read  "  finished." 

—  120,  Table,  for  "  Nochistingo,"  read  "  Nochistongo " ;  for  "  Supperton,"  read 

"  Sapperton  " ;  and  for  "  Black  Rock  W.  S."  read  "  Black  Rock  U.  S." 

—  121, 1.  19,  for  "  Belchingly,"  read  "  Blechingly." 

—  125,  in  table  at  bottom,  for  "f§,"  read  "  §§,"  and  for  "140,  T2A,  T^Q,  or 

0.13,"  read  "  111,  rW,  T¥T?  or  0.15." 

—  126,  1.  1,  for  "  extensive,"  read  "  extensile." 

—  Ifi7, 1.  10,  for  "  67,200,"  read  "  65,251." 


ADDITIONS,  ALTERATIONS,   ETC.  XV11 

Page  127, 1.  26,  for  "  Hodgekinson,"  read  "  Hodgkinson." 

—  128, 1.  4,  for  "  12000,"  read  "  11000." 

—  "    1.  15  and  22,  for  "  Hodgekinson,"  read  "  Hodgkinson." 

—  129, 1.  5,  for  "  12000,"  read  "  11000." 

—  129, 1.  2  from  bottom,  for  "  Sunwood,"  read  "  Ironwood." 

—  130, 1.  7,  for  "  WJJ-  =  4  8b d2,"  read  "  WL  =  4  Sb  rf2." 

—  131, 1.  9,  for  "  wood  143,"  read  "  wood  133." 

—  134,  in  art.  164,  for  "  700,"  read  "  952." 

—  136,  for  example  there  given,  place  the  following:  — 

Span    ...    30  feet,  Whence  — 

Length  ...  34    "  Length    ....    34.  feet, 

Load    ...    10  tons  at  centre.  Span 30    " 

6  x  10  x  12  x  30  _  Depth      .    ...    25}  inches, 

34  x  12  Lower  flange      .    .  32.58  square  inches, 

16  Upper  flange    .    .      5.34        "         " 

,  32.58 
and  — —  =  5.34. 

D.I 

—  141,  last  line,  Fig.  63  A  was  omitted;  it  is  the  same  as  fig.  102,  page  200,  in 

verted. 

—  142,  last  line,  for  "  span,"  read  "  spans." 

—  146,  head  of  col.  7,  for  "  top  washer,"  read  "  thickness  of  washer." 

—  150,  after  line  9,  figs.  67  D  and  67  E  (page  153)  should  be  inserted. 

—  151, 1.  3,  for  "  W  =  2249,"  etc.,  read  "  W  =  2240,"  etc. 

—  "    1.  18,  for  "  opposite  to  31,416,  is  the  diam.  1|,"  read  "  opposite  to  41,415,  is 

the  diam.  If." 

—  "1.  19,  for  "If, "read  "If." 

—  154,  last  line,  for  "  tubular,"  read  "  tabular." 

—  156, 1.  4  from  bottom,  for  "  washer  band,"  read  "  washer  used." 

—  164, 1.  10  to  14,  inclusive.     The  first  number  of  ratios  should  be  20  instead  of  15. 

—  166,  1.  11,  for  "  69  B,"  read  "  69  A." 

—  171,  head  of  col.  5  of  table,  for  "  rod  of  arch,"  read  "  rad.  of  arch." 

—  173, 1.  25,  for  "  ability,"  read  "  stability." 

—  "    1.  32,  for  "  Whence,"  read  "  where." 

—  175,  i.  8,  for  "triangular,"  read  "diagonal." 

—  178, 1.  3,  for  "article,"  read  "outside." 

— .184, 1.  4  from  bottom,  for  "barriers,"  read  "  voussoirs." 

—  187,  fig.  96  is  upside  down;  also,  fig.  97,  page  188,  and  fig.  98,  page  189. 

—  193, 1.  4,  col.  3  of  table,  for  "  .00000675,"  read  "  .00000685  " ;  also,  1.  16,  col.  5,  for 

"  straining,"  read  "  shearing  " ;  1.  7  from  bottom,  for  "  15,000,"  read  "  18,000 ;" 
and  1.  6  from  bottom,  for  "  75,000,"  read  "  105,000." 

—  199, 1.  7  from  bottom,  for  "20,132,"  read  "  20,312." 

— -  200, 1.  4,  for  "  A  C,"  read  "  A  G  " ;  and  1.  6,  for  "  that  on  A  E,"  read  "  that  on 
AK." 

—  202, 1.  7,  for  "  on  page  193,"  read  "  on  page  138." 

—  204, 1.  5  from  bottom,  for  "  varied  line,"  read  "  versed  sine." 


XVU1  ADDITIONS,   ALTERATIONS,   ETC. 

,  L  6  and  i,  far  «  F  G,  G  E,  in  phee  of  E  F,  E  C,"  read  u  G  L,  G  E,  in  pfece 
«fFL,FC." 


where  Z>  =  depression, 

half  length  of  curve  before 


P  —  half  length  of  curve  after  elongation, 

d  =  h*lf  distance  between  points  of  suspension.'*    Omit  the  remain 

der  of  the  paragraph. 

211,  omit  the  6th  and  7th  lilies,  and  in  place  of  fonnnla  Acre  given,  use  that  on 
p*ge  210,  (as  corrected,)  F  being  the  length  of  semi-curve  as  elongated  bv 
heat  mstead  of  by  tenskm;  the  elongations,  both  by  heat  and  tension,  being 
found  by  table  on  page  193. 


~~  :'.r   ;-  .:::;  :  ;. 

213  and  214.  The  remarks  under  "Anchoring  Masonry,"  are  evidently  wrong 
throughout:  1st,  Ac  whole  tension  should  be  divided  by  two,  instead  of 
/«•-,  as  half  of  the  whole  tension  acts  at  each  point  of  suspension;  2d,  no 
redwtioB  should  ly  made  ftr  the  directian  of  the  pulling  force.  One  half  of 
the  tension  is  3,321^50  fts.;  which  is  resisted  by  a  column  of  masonry  of 
3.32L250 

x  15x91 


feet 

214,  L  6,  for  u  561^»,w  read  u  562^42." 
US,  L  14  from  bottom,  ftr  "stiffemog  towers,"  read  uctiffenmg  trnaMa. 

225,  L  14,  for  "194,"  read  "193." 

08,  L  «,  fcr  B  see  p.  B8,"  read  "  see  p.  193." 

«7,  L  4,  for  "detensional,"  read  "  detrusionaL" 

2M,  in  place  of  equations  at  L  16,  put  •»  J?  x  a  =  J^  x  (2  </  x  f), 


where  a  =  area  of  rivet, 
d=  distance, 
t  =  plate  thickness. 

229,  in  art  242,  the  strengths  of  "  wrought  mm,"  have  been  taken  for  those  of 
"  bofler  plate"  ;  that  is,  11,000  for  7,50*,  sad  15,000  for  12,740,  which  is  wrong. 
231,  L  21,  for  "  chopped,"  read  «  dropped." 
2»4,  L  4,  for  "joint,"  read  «jwLw 
«8,  L  14,  for  "  0.016  feet,"  read  "  0.047  feet." 
236,1.  9,  for  "care,"  read  "ease," 
MT,  L  9  from  bottom,  for  "refnMating,"  read  «  separating." 

241,  L  2,  for  "  localities,"  read  "  locality." 

242,  L  7,  omit  "and  ce,  the  parapets." 

243,  L  9,  for  "  embenkment,"  read  "  abutment." 

244,  L  9,  for  "is  thus,"  read  "  is  found  thus." 
ttfi,  L  IT,  far  «  letter,"  read  «  batter." 


ADDITIONS,   ALTERATIONS,   ETC.  xix 

Page  249,  1.  23,  for  "  common  hydraulic,"  read  "  common  mortar,  hydraulic." 

—  "    1.  27,  for  "  argyle  magnesia,"  read  "  argil,  magnesia." 

—  251, 1.  16,  for  "  7J  to  2,"  read  "  1£  to  2." 

—  254,  last  1.,  for  "  corners,"  read  "  courses." 

—  256, 1.  13,  for  "  formed,"  read  "  found." 

—  258,  art.  276,  in  place  of  "  2^  x  15  x  i  x  IQO  x  *g»  put  "  20  *  15  *  1  *  100  x  2  x 

22p,"  where  2  represents  the  ratio  between  Ca  6,  and  6-2;  thus,  20  x  15  x 
1  x  100  x  ^|  x  2^0  =  nijlllj  for  tne  overthrowing  force  in  place  of  100,000. 
The  overthrowing  force  is  thus  large,  because  the  maximum  weight  of  earth 
has  been  assumed  to  press  against  the  wall  with  its  whole  force,  no  allowance 
being  made  for  friction.  In  practice,  -^  of  the  height  has  been  found  amply 
thick  for  walls  retaining  ordinary  earth. 

—  262,  last  1.  but  one,  for  "  superstratum,"  read  "  substratum." 

—  264,  in  example,  1.  5,  for  "  26,667,"  read  "48,000." 

—  266, 1.  25,  for  "  Godwin,"  read  "  Goodwin." 

—  "    1.  26,  for  "  There,  sands,"  read  "  These  sands." 

—  267, 1.  22,  for  "  bottom,"  read  "  proper  level." 

—  281,  1.  4  from  bottom,  for  "  curve,"  read  "  cone." 

—  282, 1.  20,  for  "  Daniel,"  read  "  David." 

—  "    1.  4  from  bottom,  for  "  cup,"  read  "  cap." 

—  284, 1.  10,  and  285, 1.  8,  for  "  compressed  rails,"  read  "  compound  rails." 

—  285, 1.  5,  for  "  extension,"  read  "  extensile." 

—  289,  invert  col.  1  of  table,  so  that  it  shall  read  — 

At  100°  place  the  rails  in  contact. 
"    90°  at  a  distance  of  .00136  feet,  or  0.016  niches. 
"     80°         "        *»         .00272      "       0.032      "        Etc. 

—  289,  last  1.,  for  "  levelled,"  read  "  bevelled." 

—  291,  last  1.,  for  "  a  c,  4.8,"  read  "a  c,  L  8." 

—  292, 1.  9,  for  "eh  and  d £,"  read " e  L  and  d k " ;  same  p. .1.  6  from  bottom,  for  " a, 

9  is  three,  etc."  read  "  a  b  is  three,"  etc. 

—  293, 1.  6  and  7,  for  "ig,  eh,bb,  8,  9,  A  s79,"  read  "  ig,  eh,  ac,  Jc." 

—  296, 1.  14,  for  "  JP  —  K^2»  read  "  J23  — J2^a." 

—  303,  art.  299,  for  "  M.  Leguire,"  read  "  M.  Seguin." 

—  306, 1.  2,  for  "  B.  R.  and  G.,"  read  "  R.  K.  and  G." 

—  314, 1.  2,  for  "  D.  R.  Clark,"  read  "  D.  K.  Clark." 

—  320, 1. 1,  for  "  Railroad,  three  pounds  (Pennsylvania),"  read  "Railroad  (Penn 

sylvania),  three  pounds." 

—  "   1.  7,  for  "  coal,"  read  "  coke." 

—  331,  near  bottom,  for  "  The  area  is,  therefore, 

Sides,  twice  length,  etc.,  read  "  Sides,  twice  length  by  height,  etc., 
Back,  twice  height,  etc.,  Back,  height  by  width,  etc., . 

Front,  twice  height,  etc.,  Front,  height  by  width,  .etc.,. 

Top,  twice  length,  etc.,"  Top,  length  by  width,  .etc.'" 


XX  ADDITIONS,   ALTERATIONS,   ETC. 

Page  334,  1.  15,  for  "  44.7  Ibs.,"  read  "  14.7  Ibs." 

—  335,  1.  7,  for  "  Railway  Mechanics,"  read  "Railway  Machinery." 

—  "    1.  10,  for  "  two  velocities,"  read  "  low  velocities." 

—  336,  last  L,  for  "  entering  part,"  read  "  entering  port." 

—  341,  1.  11,  for  "properties,"  read  "proportions." 

—  "    last  1.,  for  "  Nollan,"  read  "  Nollau." 

—  346,  1.  17,  for  "part,"  read  "port,"  and  for  "construction,"  read  "contrac 

tion." 

—  355,  1.  7,  for  "  6300,"  read  "  5170  "  ;  and  1.  9,  for  "  16,905,"  read  "  15,775." 

—  363,  1.  17,  for  "  44  x  2  =  80,"  read  "  44  x  2  =  88." 

—  "  1.  18,  for  "  54£  x  3  =  103J,"  read  "  54£  x  3  =  163J." 

—  367,  1.  16,  for  "  WV'  read  "  W*-" 

—  368,  1.  15,  for  "  u  =  135,"  read  "  n  =  135,"  etc. 
-  370,  1.  7,  for  "  feet,"  read  "  per  cent." 

—  376,  for  "  19090,"  read  "  19050." 

5280 

—  384,  in  last  part  of  example,  for  "  ^Ts  1415  X  4  =  37300>" 


—  421,  bottom  line,  for  "  decision,"  read  "  division." 

—  423  and  424,  in  table,  for  "  count,"  read  "  cost." 

—  427,  1.  32,  for  "  which,"  read  "  we." 

—  428,  1.  4,  transpose  "  Dr.  Lardner,  (1850,)  "  to  the  end  of  line  3. 


-443, 

—  446, 

—  459, 


-461, 

—  468, 

—  474, 
-479, 


28,  for  "  valuation,"  read  "  solution." 
11,  for  "attained,"  read  "obtained." 

20,  for  "  Hectametre,"  read  "  Hectometre." 

21,  for  "  Ridometre,"  read  "  Kilometre."     • 
7,  for  "  less  than  a,  or  o,"  read  "  less  a,  or  0." 
30,  for  "  fractions,"  read  "  functions." 

18,  for  "  Balbett,"  read  "  Babbitt." 

10,  for  "one  sixth,  with  much  less,"  read  "one  sixth;  with  sand,  much 


less.' 


HANDBOOK 


OP 


RAILROAD    CONSTRUCTION. 


INTRODUCTION. 


"  They  bnild  not  merely  roads  of  earth  and  stone,  as  of  old,  but  they  build  iron 
roads :  and  not  content  with  horses  of  flesh,  they  are  building  horses  of  iron,  such 
as  never  faint  nor  lose  their  breath."  —  DR.  BUSHNEUU 


KISE   AND    PBOGEESS    OF    RAILROADS. 

1.  IN  1825,  the  Stockton  and  Darlington  Railroad  (Eng 
land),  was  opened. 

In  1827,  the  Quincy  (of  Massachusetts),  and  Mauch- 
Chunk  (Pennsylvania),  were  completed. 

In  1829,  the  Liverpool  and  Manchester  road,  (England), 
was  finished. 

In  1833,  a  road  was  opened  from  Charleston,  (South 
Carolina),  to  Augusta  (Georgia). 

In  1840,  Belgium  opened  190  miles  of  railroad. 

In  1843,  the  railroad  from  Paris  to  Rouen  (France), 
was  completed. 


2  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

In  1844,  Belgium  finished  her  system  of  347  miles. 

In  1846,  Russia  opened  a  railroad  from  the  Wolga  to  the 
Don. 

In  1847,  Germany  had  in  operation  2,828  miles. 

In  1852,  the  Moscow  and  St.  Petersburg  road  was 
finished. 

2.  In  1856,  the  United  States  of  America  had  in  opera 
tion  23,000  miles,  and  in  progress  17,000  miles ;  employing 
6,000  locomotive  engines,  10,000  passenger  and  70,000 
freight  cars ;  costing  in  all  about  750,000,000  of  dollars ; 
running  annually  114,000,000  miles,  and  transporting  123£ 
millions  of  passengers,  and  30  millions  of  tons  of  freight  per 
annum ;  performing  a  passenger  mileage  of  4,750,000,000, 
and  a  freight  mileage  of  3,000,000,000. 

3.  By  mileage  is  meant  the  product  of  miles  run,  by  tons  or  by  passengers 
carried.  Thus,  500  persons  carried  100  miles,  and  750  persons  carried  75  miles, 
give  a  passenger  mileage  of 

500  X  100  +  750  X  75  =  106,250. 

4.  The  rate  of  progress  in  the  United  States  has  been  as 
follows :  — 

In  1828,  there  were  3  miles. 
In  1830,  41  miles. 

In  1840,  2,167  miles. 

In  1850,  7,355  miles. 

In  1856,  23,242  miles. 

At  the  present  time,  January  1,  1857,  there  is  probably,  in 
round  numbers,  25,000  miles  of  completed  road,  or  enough 
to  extend  entirely  around  the  world.  As  regards  the  ratio 
of  completed  road  to  population,  and  as  regards  the  actual 
length  of  railroad  in  operation,  the  United  States  stand  be 
fore  any  other  country. 


INTRODUCTION. 


INFLUENCE  OF  RAILROADS. 

5.  The  effect  of  a  judicious  system  of  railroads  upon 
any  community  is  to  increase  consumption  and  to  stimulate 
the  production  of  agricultural  products ;  to  distribute  more 
generally  the  population,  to  cause  a  balance  between  sup 
ply  and  demand,  and  to  increase  both  the  amount  and 
safety  of  travelling.  It  is  stated  that  within  two  years 
after  the  opening  of  the  New  York  and  Erie  Railroad,  it 
was  carrying  more  agricultural  produce  than  the  entire 
quantity  which  had  been  raised  throughout  the  tributary 
country  before  the  road  was  built. 

6.   The  following  table,  cut  from  a  Chicago  paper,  shows  the  effect  of  railroad 
transport  upon  the  cost  of  grain  in  that  market :  — 


WHEAT. 

CORN. 

ByR.  R. 

By  Wagon. 

By  R.  R. 

By  Wagon. 

At  market,  $49.50 

$49.50 

$25.60 

$25.60 

10  miles,    49.25 

48.00 

24.25 

23.26 

50  miles,    48.75 

42.00 

24.00 

17.25 

100  miles,     48.00 

34.50 

23.25 

9.75 

150  miles,     47.25 

27.00 

22.50 

2.25 

200  miles,    46.50 

19.50 

21.75 

0.00 

250  miles,     45.75 

12.00 

21.00 

0.00 

300  miles,    45.00 

4.50 

20.25 

0.00 

330  miles,    44.55 

0.00 

19.80 

0.00 

Thus  a  ton  of  corn  carried  two  hundred  miles,  costs,  per 
wagon  transport,  more  than  it  brings  at  market ;  while 
moved  by  railroad,  it  is  worth  $21.75  per  ton.  Also  wheat 
will  not  bear  wagon  transport  of  three  hundred  and  thirty 
miles ;  while  moved  that  distance  by  railroad  lit  is  worth 
$44.55  per  ton. 

7.   By  railroads,   large   cities    are    supplied  with   fresh 
meats   and  vegetables,  butter,  eggs,  and  milk.      An  un- 


4  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

healthy  increase  of  density  of  population  is  prevented,  by 
enabling  business  men  to  live  five,  ten,  or  fifteen  miles 
away  from  the  city  and  yet  do  business  therein.  The 
amount  of  this  diffusion  is  as  the  square  of  the  speed  of 
transport.  If  a  person  walks  four  miles  per  hour,  and  sup 
posing  one  hour  allowed  for  passing  from  the  house  to  the 
place  of  business,  he  cannot  live  at  a  greater  distance  than 
four  miles  from  his  work.  The  area,  therefore,  which  may 
be  lived  in,  is  the  circle  of  which  the  radius  is  four,  the  di 
ameter  eight,  and  the  area  fifty  and  one  quarter  square 
miles.  If  by  horse  one  can  go  eight  miles  per  hour,  the  di 
ameter  becomes  sixteen  miles,  and  area  two  hundred  and 
one  square  miles ;  and,  if  by  railroad  he  moves  thirty  miles 
per  hour,  the  diameter  becomes  sixty  miles,  and  the  area 
2,827  miles.  The  effect  of  such  diffusion  is  plainly  seen 
about  Boston,  (Massachusetts).  People  who  in  1830  were 
mostly  confined  to  the  city,  now  live  in  Dorchester,  Mil 
ton,  Dedham,  Roxbury,  Brookline,  Brighton,  Cambridge, 
Charlestown,  Somerville,  Chelsea,  Lynn,  and  Salem ;  places 
distant  from  two  to  thirteen  miles. 

8.  In  railroads,  as  in  other  labor  saving  (and  labor  pro 
ducing)  machines,  the  innovation  has  been  loudly  decried. 
But  though  it  does  render  some  classes  of  labor  useless,  and 
throw  out  of  employment  some  persons,  it  creates  new  la 
bor  far  more  than  the  old,  and  gives  much  more  than  it 
takes  away.  Twenty  years  of  experience  shows  that  the 
diminished  cost  of  transport  by  railroad  invariably  aug 
ments  the  amount  of  commerce  transacted,  and  in  a  much 
larger  ratio  than  the  reduction  of  cost.  It  is  estimated  by 
Dr.  Lardner,  that  300,000  horses  working  daily  in  stages 
would  be  required  to  perform  the  passenger  traffic  alone, 
which  took  place  in  England  during  the  year  1848.  It  is 
concluded,  also,  from  reliable  returns,  that  could  the  whole 
number  of  passengers  carried  by  railroad,  have  been  trans- 


INTRODUCTION. 


ported  by  stage,  the  excess  of  cost  by  that  method  above 
that  by  railroad  would  have  been  $40,000,000. 


SAFETY   OF,  RAILROAD    TRAVELLING. 

9.  If  we  know  that  in  a  given  time  the  whole  distance 
travelled  by  passengers  was  500,000  miles,  and  that  in  such 
time  there  occurred  one  fatal  accident,  it  follows  that  when 
a  person  travels  one  mile,  the  chances  are  499,999  against 
one  of  losing  life.  If  he  travel  ten  miles,  the  chances  are 
49,999  against  one,  or  ten  times  as  many  of  meeting  with 
loss  of  life ;  and  generally  the  chances  of  accident  are  as 
the  distance  travelled.  In  1855,  the  whole  number  of  miles 
run  by  passengers  in  the  United  States  was,  in  round  nun> 
bers,  4,750,000,000,  while  there  were  killed  one  hundred  and 
sixteen;  or  one  in  every  41,000,000,  very  nearly.  (The  ra 
tio  in  England  is  one  in  every  65,000,000.)  Now  if  for 
each  400,000  miles  travelled  by  stage  passengers,  (a  dis 
tance  equal  to  sixteen  times  round  the  world,)  one  passen 
ger  was  killed,  and  if  the  whole  railroad  mileage  could  be 
worked  by  stages,  there  would  be  annually  11,875  lives  lost ; 
or  one  hundred  times  the  number  annually  lost  by  railroad. 
Thus  it  would  be  one  hundred  times  safer  to  travel  by  rail 
road  than  by  stage.  The  danger  of  steamboat  travelling  is 
far  greater  than  by  stage. 


PRELIMINARY    OPERATIONS. 

10.  The  first  step  to  be  taken  in  starting  a  railroad  en 
terprise,  is  the  choice  of  a  board  of  directors  (provisional), 
whose  duty  is  to  find  all  that  can  be  known  of  the  commer 
cial,  financial,  and  agricultural  nature  of  the  country  to  be 
traversed.  To  determine  as  near  as  possible  its  ability  to 

1* 


D  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 

build  and  support  a  road;    and  to  obtain  the  necessary 
legislative  enactments. 

11.  The  determination  of  the  increase  of  traffic  which 
the  road  may  be  expected  to  excite,  is  a  difficult  matter. 
There  can  be  few  rules  given  for  proceeding  in  such  an  in 
quiry.  It  seems  very  easy  to  prove  by  what  roads  have 
done,  that  any  project  will  be  profitable. 

An  abstract  of  a  report  lately  published,  tries  to  prove  that  a  road  will  pay 
forty-five  and  one  half  per  cent,  net ;  the  working  expenses  being  assumed  at 
only  thirteen  and  one  half  per  cent,  of  the  gross  receipts.  The  error  here  lies  in 
assuming  the  working  expenses  too  low,  as  few  roads  in  the  country  have  been 
worked  for  less  than  forty  per  cent. ;  a  more  common  ratio  being  fifty  one-hun- 
dredths  of  the  gross  receipts. 

Not  one  half  of  railroads  are  built  for  the  original  esti 
mate.  In  few  cases  has  sufficient  allowance  been  made  for 
the  sacrifice  undergone  in  negotiating  the  companies'  secu 
rities.  All  general  instructions  that  can  be  given  relating 
to  the  determination  of  prospective  profits,  are,  to  keep  the 
estimate  of  constructing  and  working  expenses  high,  and 
that  of  the  assumed  traffic  low ;  not  so  low,  however,  as  to 
require  a  too  lightly  built  road. 


MECHANICAL    PRINCIPLES    OF    LOCOMOTION. 

12.  The  superiority  which  the  modern  railroad  possesses 
over  the  common,   McAdam,  plank,  or  turnpike-road,  con 
sists,  first,  in  the  reduction  of  the  resistance  to  motion,  and 
second,  in  the  application  of  the  locomotive  steam-engine. 

13.  The  effect  of  grades  of  a  given  incline  upon  a  rail 
road  is  relatively  more  than  upon  common  roads ;    for  as 
the  absolute  resistance  on  a  level  decreases,  the  relative  re 
sistance  of   grades   augments:    whence  to  obtain  the  full 
benefit  of  the   system,  we   must  reduce  much  more  the 


INTRODUCTION.  7 

grades  and  curvature  upon  a  railroad,  than  on  a  common 
road.  For  example,  if  the  resistance  to  moving  one  ton 
upon  a  level  upon  a  railroad  was  ten  pounds,  and  upon  a 
common  road  forty  pounds,  where  a  twenty-three  feet 
grade  would  be  admissible  upon  the  former,  we  might  use 
an  incline  of  ninety-three  feet  per  mile  upon  the  latter. 

14.  The  resistance  to  the  motion  of  railroad  trains  in 
creases  rapidly  with  the  speed ;  *  whence  the  grades  of  a 
passenger  road  where  a  high  average  speed  is  used,  may  be 
steeper  than  those  of  a  road  doing  a  freight  business  chiefly. 


DETERMINATION  OF  CHARACTER  OF  ROAD. 

15,  Upon  a  correct  idea  of  what  the  road  ought  to  be, 
depends  in  a  great  degree  its  success.     The  amount  of  cap 
ital  expended  upon  the  reduction  of  the  natural  surface,  de 
pends  upon  the  expected   amount  of  traffic.     The  traffic 
remaining  the  same,  the  greater  the  capital  expended  in  re 
ducing   grades  and   curvature,  the  less  will  be  the  work 
ing  expense ;    and  the   less   the   construction   capital,  the 
greater  that  for  maintenance.     The  limit  of   expenditure 
must  be  such  as  to  render  the  sum  of  construction   and 
maintaining  capital  a  minimum. 

The  bad  effect  of  grades  upon  the  cost  of  maintaining 
and  of  working  railroads,  is  not  so  great  as  many  suppose. 
Of  the  whole  cost  of  working,  only  about  forty  per  cent, 
can  be  charged  to  locomotive  power ;  and  of  this,  not  more 
than  sixty-two  per  cent,  is  effected  by  grades.f 

16.  The  degree  of  curvature  to  be  admitted  upon  any 
road  depends  somewhat  upon  the  speeds  at  which  trains 
are  to  be  run.     The  larger  the  radius  of   curvature,  the 

*  See  chapter  XIV.  t  See  appendix  F. 


8  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

greater  may  be  the  speed ;  at  the  same  time  the  elevation 
of  the  exterior  rail  upon  curves  may  be  less,  and  therefore 
more  adapted  to  freight  trains.  High  rates  of  speed  are 
considered  upon  some  competing  roads  necessary ;  but  are, 
even  in  such  cases,  necessary  evils.  The  wear  of  cars  and 
of  engines,  of  permanent  way  and  of  bridges,  increase  in  a 
rapid  ratio  with  the  velocity.  The  maximum  speed  for 
freight  trains  should  never  exceed  fifteen  miles  per  hour,  or 
for  passenger  trains  from  twenty  to  twenty-five  miles  per 
hour.* 

17.  The  agricultural  nature  of  the  country  and  its  com 
mercial  position,  will  determine  the  nature  of  the  traffic, 
whether  passenger  or  freight,  and  also  the  amount.  The 
amount  and  nature  of  the  traffic  will  limit  the  curvature, 
and  will  partially  determine  the  arrangement  of  grades. 


GAUGE. 

18.  The  question  of  broad  and  narrow  gauge  has  led  to 
much  discussion,  and  both  plans  claim  among  their  advo 
cates  some  of  the  best  engineers.  The  narrow  gauge 
(American  and  English,)  is  four  feet  eight  and  one  half 
inches  (from  inside  to  inside  of  rail).  The  maximum 
adopted,  is  (the  Great  Western  of  England)  seven  feet. 
The  American  maximum  (New  York  and  Erie,  and  Ohio 
and  Mississippi)  is  six  feet.  There  is  also  in  America 
four  feet  ten  inches,  five  feet,  and  five  feet  six  inches. 
The  advantage  of  the  broad  gauge  for  a  road  doing  an  ex 
tensive  business,  is  the  increased  stowage  room  in  freight 
cars,  thus  rendering  admissible  shorter  trains ;  by  which  the 
locomotive  power  is  more  directly  applied  on  curves.  More 


See  chapter  XVI. 


INTRODUCTION.  9 

comfortable  passenger  cars,  (the  same  length  of  car  of 
course  accommodates  the  same  number  of  passengers). 
The  disadvantages  of  a  wide  gauge  are,  increased  expense 
of  cutting,  embanking,  bridging,  and  masonry ;  increased 
expense  of  engines,  cars,  rails,  sleepers,  and  all  machinery ; 
more  wear  and  tear  upon  curves,  by  reason  of  greater  dif 
ference  between  the  lengths  of  inner  and  outer  rails,  and 
increased  atmospheric  resistance  to  fast  trains,  from  in 
creased  bulk. 

19.  The  general  conclusion  arrived  at  by  a  commission 
appointed  by  the  Great  Western  Railway  Company,  (Eng 
land,)  consisting  of  Messrs.  Nicholas  Wood,  J.  K.  Brunei, 
and  John  Hawkshaw,  was,  that  four  feet,  eight  and  one 
half  inches  was  rather  narrow,  but  still  enough  for  a  cer 
tain  class  of  roads ;  that  two  or  three  inches  made  no  ma 
terial  difference ;  that  seven  feet  was  too  wide  for  any  road ; 
that  the  weight  of  the  broad  gauge  engine,  compared  with 
the  small  increase  of  power,  was  a  serious  evil ;  that  en 
gines  could  be  run  with  perfect  safety  upon  the  narrow 
gauge  at  any  speed  from  thirty  to  sixty  miles  per  hour,  and 
that  no  more  had  been  attained  upon  the  broad ;  that  roll 
ing  friction  was  less  upon  the  broad,  owing  to  the  increased 
diameter  of  wheels,  but  that  friction  from  curves  and  at 
mospheric  resistance  was  greater. 

20.  D.  K.  Clark,  in  «  Railway  Machinery,"  p.  300,  301, 
makes  the  resistance  as  deduced  from  experiments  made 
upon  both  the  four  feet,  eight  and  one  half  inches,  and  the 
seven  feet   gauge,  considerably  greater   upon   the   former 
than  on  the  latter ;    but  as  the  narrow  gauge  trials  were 
made  upon  a  curved  road,  with  rails  in  a  bad  state,  in 
average  weather,  while  those  upon  the  broad  were  made  in 
good  weather,  upon  a  good  and  straight  line,  he  leaves  the 
gauge  question  open,  and  uses  the  same  formula  for  all 
widths. 


10  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

21.  Want  of  increased  power,  can.be  an  apology  for  in 
creased  gauge,  until  the  capacity  of  the  narrow  gauge  has 
been  filled.  The  strongest  engines  in  the  world  are  upon 
the  four  feet,  eight  and  one  half  inch  gauge.  No  engines 
in  America  surpass  or  compare  for  absolute  strength,  with 
those  upon  the  Baltimore  and  Ohio  Railroad.  The  most 
powerful  passenger  engine  ever  built  for  high  speeds,  is 
Crampton's  engine  "  Liverpool,"  (London  and  North-west 
ern  Railroad,  England,)  gauge  four  feet,  eight  and  one  half 
inches. 


GENEKAL  ESTABLISHMENT  OF  KOUTE. 

22.  The   straight   and  level    line   connecting   any   two 
points,  is  of  course  the  best  for  the  completed  road ;   but 
this  is  seldom  practicable.     Way  towns  must  be  accommo 
dated  to  a  certain  extent ;  but  the  main  line  should  not  be 
lengthened  on  that  account,  unless  the  traffic  and  capital 
furnished  by  such  town  is  not  only  sufficient  to  pay  for  the 
construction  and  maintenance  of  the  extra  length,  but  also 
to  carry  the  entire  through  traffic  over  such  increased  dis 
tance.     If  the  town  is  unable  to  support  such  a  burden,  it 
may  be  able  to  build  and  maintain  a  branch. 

23.  Routes  placed  upon  the  immediate  bank  of  a  large 
stream,  are  generally  crossed  by  a  great  number  of  deep 
gorges,  which  serve  to  drain  the  side  lands. 

24.  Routes  placed  upon  sloping  land,  when  the  axis  of 
the  road  and  the  natural  descent  are  at  right  angles  to  each 
other,  are  more  subject  to  slides  than  when  placed  upon 
plateaus  or  "  bottoms." 

25.  Lines  crossing  the  dividing  ridges  of  separate  waters, 
rise  and  fall  a  great  deal ;  thus  rendering  necessary  a  strong 
motive  power  to  work  the  road.     Such  roads  are  the  West- 


INTRODUCTION.  11 

ern  of  Massachusetts,  passing  from  the  valley  of  the 
Connecticut  at  Springfield,  to  the  Hudson  River  valley  at 
Greenbush.  Also  those  roads  crossing  the  Alleghanies. 
And  such  will  be  the  Pacific  road,  crossing  first  the  Rocky 
Mountains  to  the  Great  Basin,  and  second,  the  Sierra  Ne 
vada  into  the  Sacramento  valley. 


CHAPTER    I 
RECONNOITRE. 


26.  THE  object  of  the  reconnoitre  is  to  find   approxi 
mately  the  place  for  the  road,  (i.  e.  within  half  of  a  mile,) 
to  find  the  general   form  of  the  country,  and  to  choose 
that  part  which  with  reference  to  the  expected  traffic,  shall 
give  the  best  gradients;    to  determine   the   elevations  of 
summits  upon  competing  routes ;   and,  in  fine,  to  prepare 
the  way  for  the  survey. 

27.  The  general  topography  of  a  country  may  be  ascer 
tained  by  reference  to  State   maps,  where  such  exist,  and 
when  not,  by  riding  over  the  district.     The  direction  and 

Fig.  i.  size  of  watercourses,  will 

show  at  once  the  position 
of  summits. 

28.  Water  flowing  as 
in  fig.  1,  indicates  a  fall 
from  B  to  E ;  and  also 
transverse  slopes  from  a  a 
and  c  c  to  d  d. 


RECONNOITRF. 


13 


29.  Fig.  2  shows   a   broken  ridge  a  a  a  from  which  the 
water  flows  in  both  di-  Fig  2 

rections;  and  in  gen 
eral,  the  sources  of 
streams  point  towards 
the  higher  lands. 

30.  If  it  be  required 
to    join  the  points  A 
and  D  by  railroad,  (fig. 
3,)  it  may  be  better  to 

pass  at  once  from  A  through  B  and  C,  than  to  go  by  the 

Fig.  3. 


streams  F  E,  F'  E'.  By  the  latter  route  the  road  would 
ascend  all  of  the  way  from  A  to  E  ;  and  descend  from  E"  to 
D.  By  the  first  if  it  requires  steep  gradients  to  rise  from  A 
to  B,  and  to  fall  from  C  to  D,  still  if  tfae  section  B  C  is  ft- 
plateau,  and  if  the  rise  between  A  and  B  and  A  and  E  is 
the  same,  by  grouping  the  grades  at  B  and  C  we  may  so 
adapt  the  motive  power,  as  to  take  the  same  train  from  A\ 

2 


14 


HANDBOOK    OF   RAILROAD    CONSTRUCTION. 


to    D    without   breaking. 


Fte.  4. 


The  general  arrangement  of 
grades  by  the  line 
A  B  C  D  is  then  as 
fig.  4 ;  and  by  A  F  E 
E'  F'  D,  as  in  fig.  5. 
The  saving  in  this 
case  is  by  length,  as 

Fig.  5. 


the  same  amount  of  power  is  required  to  overcome  a  given 
ascent. 

31.  Valleys  generally  rise  much  faster  near  their  source, 
than  at  any  point  lower  down  ;  also  the  width  increases  avS 
we  approach  the  debouch.  Fig.  6  shows  the  cross  sections 
of  a  valley  from  its  source  to  the  mouth. 

Fig.  6. 


32.    In  the  case  of  parallel  valleys  running  in   the   same 


RECONNOITRE. 


15 


direction,  the  form  will   be  as  in  fig  7.     Let  1  2,  1  2,  etc., 

represent  a  da-  Fig.  7. 

turn   level,    or 

a       horizontal 

plane   passing 

through       the 

lowest     point. 

The    line    ah, 

shows       the 

height    of   the 

bottom  at  B ;  c  d  that  at  D,  e  f  that  at  E,  and  g-h  that  at 

C.     The  broken  lines  a,  k,  /,  m,  n,  show  the  general  form  of 

the  land.     Now  by  the  route   m  m  m  m,  from   A  to  F,  we 

have    the    profile   mmmm,  fig.   8,  by  nnnn,   the    profile 

Fig.  8. 


nnnn,  and  by  o  o  o,  the  profile  o  o  o. 

33.    In  the  case  of  parallel  valleys  running  in  opposite 
directions,  as  in  fig.  9,  we  have  the  form  there  shown ;  and 

Fig.  9. 


the  profiles  corresponding  to  the  several  lines  are  shown  in 


16  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

fig.  10.  As  we  should  always  adopt  the  line  giving  the 
least  rise  and  fall,  other  things  being  equal,  it  is  plain 
which  line  on  the  plan  we  must  follow. 

Fig.  10. 


34.  In  passing  from  A  to  B,  figs.  11  and  12,  by  the  sev 
eral  lines  c,  d,  e,f,  we  have  the  profiles  shown  at  c,  d,  6>,  /, 
from  which  it  appears,  that  the  nearer  we  cross  to  the  heads 
of  streams,  the  less  is  the  difference  of  heights. 


Fig.  11. 


RECONNOITRE. 

Fig.  12. 


17 


35.    If  we  wish  to  go  from  A  to  B,  fig.  12  (a),  we  should 
of     course  ng.  12  (a). 

take  first  the 
straight  line ; 
but  being 

o 

obliged  to 
avoid  the  hill 
C,  on  arriv 
ing  at  d<  we 
should  not 
try  to  recover 
that  line  at 

but  proceed  at  once  to  B.  Also  as  we  are  obliged  to  pass 
through  d,  we  ought  to  go  directly  to  d  and  not  by  the  way 
of  c;  and  the  same  idea  is  repeated  between  A  and  d;  the 
last  line  being  AbdE.  Few  rules  can  be  given  in  the 
choice  of  routes.  Practice  only  will  enable  the  engineer  to 
find  the  best  location  for  a  railroad. 

2* 


18  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


BAROMETRICAL  LEVELLING. 

36.  The  relative  height  of  summits,  the  rate  of  fall  of 
streams,  and   absolute   elevation,  within  a  few  feet,  may 
be   easily,  rapidly,   and  cheaply   found  by  the  barometer. 
This  also  affords  an  excellent  check  upon  subsequent  lev 
elling  operations.     The  results  thus  obtained  depend  upon 
the  physical  property,  that  the  density  of  the  air  decreases 
as  the  square  of  the  height. 

37.  The  barometer  is  a  glass  tube,  partly  filled  with  mer 
cury,  having  a  vacuum  in  the  upper  part.     By  it  the  exact 
density  of  the  air  at  any  point  is  determined.     Accompany 
ing  are  two  thermometers ;  one  attached,  showing  the  tem 
perature  of  the  barometer ;  the  other  detached,  showing  the 
atmospheric  temperature. 

38.  Knowing  now  the  manner  of  finding  the  density  of 
the  air  at  any  two  points,  and  also  the  relation  between 
density  and  height,  the  operation  of  levelling  by  the  barom 
eter  is  very  simple. 

The  modus  operandi  is  as  follows,  (see  tables   A,  B,  C, 
and  D) : — 

Let  us  have  the  notes. 

Barom.  Attached  Therm.  Detached  Therm. 

Upper  Station,       29.75  28.5  27.9 

Lower  Station,       26.80  36.9  36.3 

Latitude  46°  N. 

We  have  by  table  A,  against  the  bar.  point,  29.75,  6108.6 

also  "       "      "         "  "          "       26.80,  5276.6 

The  difference       832.0 
Diff.  of  attached  therm.  36.8°  —  28.5°  =  8.3°  (table  B)  —12.2 

819.8 


RECONNOITRE.  19 

Double  the  sum  of  detached  thermometers  multiplied 
V  T<yW  of  819.8  is 

2  (27.9  +  36.3)  X  .8198  =  +  105.3 

925.1 

Correction  (see  table  C)  for  lat.  46°  N.  and  approxi 
mate  height  925.1  +3.1 

928.2 

Final  correction  by  table  B.  The  barometer  at  the  lower  station 
being  26.80,  and  the  tabular  number  against  27.56  being  0.22,  that 
for  26.80  will  be  0.31,  and  we  have 

1000  to  .31  as  928.2  to  0.287,  or  0.3, 
which  add  to  928.2  and  we  have  as  the  final  height 

928.5  metres,  or  928.5  X  3.28  —  3045.48  feet. 

The  tables  above  referred  to,  are  those  of  Mr.  Oltraan, 
and  are  considered  as  the  most  convenient  and  reliable  of 
any  published. 


20 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


TABLE    A. 


English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

14.5G 

418.5 

16.30 

1313.3 

18.03 

2117.6 

19.76 

2848.1 

14.61 

440.0 

16.34 

1332.5 

18.07 

2135.0 

19.80 

2864.0 

14.65 

461.5 

16.38 

1351.7 

18.11 

2152.3 

19.84 

2879.8 

14.68 

482.9 

16.42 

1370.8 

18.15 

2169.6 

19.88 

2895.6 

14.72 

504.2 

16.46 

1389.9 

18.19 

2186.9 

19.92 

2911.3 

14.76 

525.4 

16.50 

1408.9 

18.23 

2204.1 

19.96 

2927.0 

14.80 

546.6 

16.54 

1427.9 

18.27 

2221.3 

20.00 

2942.7 

14.84 

567.8 

16.57 

1446.8 

18.31 

2238.4 

20.04 

2958.4 

14.88 

588.9 

16.61 

1465.7 

18.35 

2255.5 

20.08 

2974.0 

14.92 

609.9 

16.65 

1484.7 

18.39 

2272.6 

20.12 

2989.6 

14.96 

630.9 

16.69 

1503.4 

18.42 

2289.6 

20.16 

3005.2 

15.00 

651.8 

16.73 

1522.2 

18.46 

2306.6 

20.20 

3020.7 

15.04 

672.7 

16.77 

1540.8 

18.50 

2323.6 

20.24 

3036.2 

15.08 

693.5 

16.81 

1559.5 

18.54 

2340.5 

20.28 

3051.7 

15.12 

714.3 

16.85 

1578.2 

18.58 

2357.4 

20.31 

3067.2 

15.16 

735.0 

16.89 

1596.8 

18.62 

2374.2 

20.35 

3082.6 

15.20 

755.6 

16.93 

1615.3 

18.66 

2391.1 

20.39 

3097.9 

15.24 

776.2 

16.97 

1633.8 

18.70 

2407.9 

20.43 

3113.3 

15.28 

796.8 

17.01 

1652.2 

18.74 

2424.6 

20.47 

3128.6 

15.31 

817.3 

17.05 

1670.6 

18.78 

2441.3 

20.51 

3143.9 

15.35 

837.8 

17.09 

1689.0 

18.82 

2458.0 

20.55 

3159.2 

15.39 

858.2 

17.13 

1707.3 

18.86 

2474.6 

20.59 

3174.4 

15.43 

878.5 

17.17 

1725.6 

18.90 

2491.3 

20.63 

3189.7 

15.47 

898.8 

17.20 

1743.8 

18.94 

2507.9 

20.67 

3204.9 

15.51 

919.0 

17.24 

1762.1 

18.98 

2524.3 

20.71 

3220.0 

15.55 

939.2 

17.28 

1780.3 

19.02 

2540.8 

20.75 

3235.1 

15.59 

959.3 

17.32 

1798.4 

19.05 

2557.3 

20.79 

3250.2 

15.63 

979.4 

17.36 

1816.5 

19.09 

2573.7 

20.83 

3265.3 

15.67 

999.5 

17.40 

1834.5 

19.13 

2590.2 

20.87 

3280.3 

15.71 

1019.5 

17.44 

1852.5 

19.17 

2506.6 

20.90 

3295.3 

15.75 

1039.4 

17.48 

1870.4 

19.21 

2622.9 

20.94 

3310.3 

15.79 

1059.3 

17.52 

1888.3 

19.25 

2639.2 

20.98 

3325.3 

15.83 

1079.1 

17.56 

1906.2 

19.29 

2655.4 

21.02 

3340.2 

15.87 

1098.9 

17.60 

1924.0 

19.33 

2671.6 

21.06 

3355.1 

15.91 

1118.6 

17.64 

1941.8 

19.37 

2687.9 

21.10 

3370.0 

15.95 

1138.3 

17.68 

1959.6 

19.41 

2704.1 

21.14 

3384.8 

15.98 

1157.9 

17.72 

1977.3 

19.45 

2720.2 

21.18 

33.99.6 

16.02 

1177.5 

17.76 

1994.9 

19.49 

2736.3 

21.22 

3414.4 

16.06 

1197.1 

17.79 

2012.6 

19.53 

2752.3 

21.26 

3429.2 

16.10 

1216.6 

17.83 

2030.2 

19.57 

2768.3 

21.30 

3443.9 

16.14 

1236.0 

17.87 

2047.8 

19.61 

2784.4 

21.34 

3458.6 

16.18 

1255.4 

17.91 

2065.3 

19.65 

2800.4 

21.38 

3473.3 

16.22 

1274.8 

17.95 

2082.8 

19.68 

2816,3 

21.42 

3487.9 

16.26 

1294.1 

17.99 

2100.2 

19.72 

2832.2 

21.46 

3502.5 

RECONNOITRE. 


21 


TABLE    A,  Continued. 


English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

21.50 

3517.2 

23.23 

4134.3 

24.96 

4707.1 

26.69 

5241.4 

21.54 

3531.8 

23.27 

4147.8 

25.00 

4719.7 

26.73 

5253.2 

21.57 

3546.3 

23.31 

4161.3 

25.04 

4732.2 

26.77 

5264.9 

21.61 

3560.8 

23.35 

4174.7 

25.08 

4744.7 

26.81 

5276.6 

21.65 

3575.3 

23.39 

4188.1 

25.12 

4757.2 

26.85 

5288.3 

21.69 

3589.8 

23.43 

4201.5 

25.16 

4769.7 

26.89 

5300.0 

21.73 

3604.2 

23.46 

4214.9 

25.20 

4782.1 

26.93 

5311.6 

21.77 

3618.6 

23.50 

4228.2 

25.24 

4794.6 

26.97 

5323.2 

21.81 

3633.0 

23.54 

4241.6 

25.28 

4807.0 

27.01 

5334.8 

21.85 

3647.4 

23.58 

4254.9 

25.31 

4819.4 

27.05 

5346.4 

21.89 

3661.7 

23.62 

4268,2 

25.35 

4831.7 

27.09 

5358.0 

21.93 

3676.0 

23.66 

4281.4 

25.39 

4844.1 

27.13 

5369.6 

21.97 

3690.3 

23.70 

4294.7 

25.43 

4856.4 

27.17 

5381.1 

22.01 

3704.6 

23.74 

4307.9 

25.47 

4868.7 

27.21 

5392.7 

22.05 

3718.8 

23.78 

4321.1 

25.51 

4881.0 

27.25 

5404.2 

22.09 

3733.0 

23.82 

4334.3 

25.55 

4893.3 

27.28 

5415.6 

22.13 

3747.2 

23.86 

4347.4 

25.59 

4905.6 

27.32 

5427.2 

22.17 

3761.3 

23.90 

4360.5 

25.63 

4917.8 

27.36 

5438.7 

22.20 

3775.4 

23.94 

4373.7 

25.67 

4930.0 

27.40 

5450.1 

22.24 

3789.5 

23.98 

4386.7 

25.71 

4942.2 

27.44 

5461.5 

22.28 

3803.6 

24.02 

4399.8 

25.75 

4954.4 

27.48 

5472.9 

22.32 

3817.7 

24.06 

4412.8 

25.79 

4966.6 

27.52 

5484.3 

22.36 

3831.7 

24.09 

4425.9 

25.83 

4978.7 

27.56 

5495.7 

22.40 

3845.7 

24.13 

4438.9 

25.87 

•  4990.9 

27.60 

5507.1 

22.44 

3859.7 

24.17 

4451.9 

25.91 

5003.0 

27.64 

5518.4 

22.48 

3873.7 

24.21 

4464.8 

25.94 

5015.1 

27.68 

5529.8 

22.52 

3887.6 

24.25 

4477.7 

25.98 

5027.2 

27.72 

5541.1 

22.56 

3901.5 

24.29 

4490.7 

26.02 

5039.3 

27.76 

5552.4 

22.60 

3915.4 

24.33 

4503.6 

26.06 

5051.2 

27.80 

5563.7 

22.64 

3929.3 

24.37 

4516.4 

26.10 

5063.2 

27.84 

5575.0 

22.68 

3943.1 

24.41 

4529.3 

26.14 

5075.3 

27.87 

5586.2 

22.72 

3956.9 

24.45 

4542.1 

26.18 

5087.2 

27.91 

5597.5 

22.76 

3970.7 

24.49 

4554.9 

26.22 

5099.2 

27.95 

5608.7 

22.80 

3984.5 

24.53 

4567.7 

26.26 

5111.2 

27.99 

5619.6 

22.83 

3998.2 

24.57 

4580.5 

26.30 

5123.1 

28.03 

5631.1 

22.87 

4011.9 

24.61 

4593.2 

26.34 

5135.0 

28.07 

5642.2 

22.91 

4025.6 

24.65 

4606.0 

26.38 

5146.9 

28.11 

5653.4 

22.95 

4039.3 

24.68 

4618.7 

26.42 

5158.8 

28.15 

5664.6 

22.99 

4052.9 

24.72 

4631.4 

26.46 

5170.6 

28.19 

5675.7 

23.03 

4066.6 

24.76 

4644.0 

26.50 

5182.5 

28.23 

5686.8 

23.07 

4080.2 

24.80 

4656.7 

26.54 

5194.3 

28.27 

5697.9 

23.11 

4093.8 

24.84 

4669.3 

26.57 

5206.1 

28.31 

5709.0 

23.15 

4107.3 

24.88 

4682.0 

26.61 

5217.9 

28.35 

5720.1 

23.19 

4120.8 

24.92 

4694.5 

26.65 

5229.7 

28.39 

5731.1 

22 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


TABLE    A,  Continued. 


English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

English 
Inches. 

Metres. 

28.43 

5742.1 

29.09 

5927.5 

29.76 

6108.6 

30.43 

6285.7 

28.46 

5753.1 

29.13 

5938.2 

29.80 

6119.1 

30.47 

6296.0 

28.50 

5764.2 

29.17 

5949.0 

29.84 

6129.6 

30.51 

6306.2 

28.54 

5775.1 

29.21 

5959.7 

29.88 

6140.1 

30.55 

6316.5 

28.58 

5786.1 

29.25 

5970.4 

29.92 

6150.6 

30.59 

6326.7 

28.62 

5797.1 

29.29 

5981.2 

29.96 

6161.1 

30.63   !   6337.0 

28.66 

5808.0 

29.33 

5991.9 

30.00 

6171.5 

30.67      6347.2 

28.70 

5819.0 

29.37 

6002.5 

30.04 

6182.0 

30.71 

6357.4 

28.74 

5829.9 

29.41 

6013.2 

30.08 

6192.4 

30.75 

6367.6 

28.78 

5840.8 

29.45 

6023.8 

30.12 

6202.8 

30.79 

6377.8 

28.82 

5851.7 

29.49 

6034.4 

3.0.16 

6213.2 

30.83      6388.0 

28.86 

5862.5 

29.53 

6045.1 

30.20 

6223.6 

30.87      6398.2 

28.90 

5873.4 

29.57 

6055.7 

30.24 

6234.0 

30.91 

6408.3 

28.94 

5884.2 

29.61 

6066.3 

30.28 

6244.4 

30.94 

6418.5 

28.98 

5894.9 

29.65 

6076.9 

30.32      6254.7 

30.98 

6428.6 

29.02 

5905.8 

29.69 

6087.5 

30.35 

6265.0 

31.02 

6438.7 

29.06 

5916.7 

29.72 

6098.0 

30.39 

6275.4 

31.06 

6448.8 

| 

TABLE    B. 


Deg. 

Met. 

Deg. 

Met. 

Deg. 

Met. 

Deg. 

•  Met. 

Deg. 

Met. 

0.2 

0.3 

4.2 

6.2 

8.2 

12.1 

12.2 

17.9 

16.2 

23.8 

0.4 

0.6 

4.4 

6.5 

8.4 

12.4 

12.4 

18.2 

16.4 

24.1 

0.6 

0.9 

4.6 

6.8 

8.6 

12.6 

12.6 

18.5 

16.6 

24.4 

0.8 

1.2 

4.8 

7.1 

8.8 

12.9 

12.8 

18.8 

16.8 

24.7 

.0 

1.5 

5.0 

7.4 

9.0 

13.2 

13.0 

19.1 

17.0 

25.0 

.2 

1.8 

5.2 

7.6 

9.2 

13.5 

13.2 

19.4 

17.2 

25.3 

.4 

2.1 

5.4 

7.9 

9.4 

13.8 

13.4 

19.7 

17.4 

25.6 

.6 

2.3 

5.6 

8.2 

9.6 

14.1 

13.6 

20.0 

17.6 

25.9 

.8 

2.6 

5.8 

8.5 

9.8 

14.4 

13.8 

20.3 

17.8 

26.2 

2.0 

2.9 

6.0 

8.8 

10.0 

14.7 

14.0 

20.6 

18.0 

26.5 

2.2 

3.2 

6.2 

9.1 

10.2 

15.0 

14.2 

20.9 

18.2 

26.8 

2.4 

3.5 

6.4 

9.4 

10.4 

15.3 

14.4 

21.2 

18.4 

27.1 

2.6 

3.8 

6.6 

9.7 

10.6 

15.6 

14.6 

21.5 

18.6 

27.4 

2.8 

4.1 

6.8 

10.0 

10.8 

15.9 

14.8 

21.8 

18.8 

27.7 

3.0 

4.4 

7.0' 

10.3 

11.0 

16.2 

15.0 

22.1 

19.0 

28.0 

3.2 

4.7 

7.2 

10.6 

11.2 

16.5 

15.2 

22.4 

19.2 

28.2 

3.4 

5.0 

7.4 

10.9 

11.4 

16.8 

15.4 

22.7 

19.4 

28.5 

3.6 

5.3 

7.6 

11.2 

11.6 

17.1 

15.6 

22.9 

19.6 

28.8 

3.8 

5.6 

7.8 

11.5 

11.8 

17.4 

15.8 

23.2 

19.8 

29.1 

4.0 

5.9 

8.0 

11.8 

12.0 

17.6 

16.0 

23.5 

20.0 

29.4 

The  degrees  refer  to  the  centigrade  thermometer. 


RECONNOITRE. 


TABLE    C. 


:  Approximate 
Height, 

0° 

15° 

40° 

55° 

Approximate 
Height. 

0° 

15° 

40" 

5^ 

200 

1.2 

1.0 

0.6 

0.4 

3200 

19.1 

18.0 

11.5 

7.0 

400 

2.4 

2.2 

1.4 

0.8 

3400 

2(X5 

19.3 

12.4 

7.7 

600 

3.4 

3.2 

2.0 

1.2 

3600 

21.8 

20.4 

13.4 

8.2 

800 

4.5 

4.3 

2.8 

1.7 

3800 

23.1 

21.6 

14.3 

8.7 

1000 

5.7 

5.3 

3.4 

2.2 

4000 

24.6 

22.9 

15.1 

9.4 

1200 

7.0 

6.4 

4.2 

2.6 

4200 

25.9 

24.3 

15.9 

10.1 

1400 

8.2 

7.6 

4.8 

3.0 

4400 

27.5 

25.8 

16.9 

10.8 

1600 

9.2 

8.8 

5.6 

3.4 

4600 

28.9 

27.1 

18.0 

11.5 

1800 

10.4 

9.8 

6.3 

3.8 

4800 

30.4 

28.4 

19.0 

12.1 

2000 

11.6 

11.0 

7.0 

4.2 

5000 

31.8 

29.8 

19.9 

12.7 

2200 

12.8 

12.1 

7.6 

4.6 

5200 

33.0 

31.0 

20.8 

13.3 

2400 

14.0 

13.3 

8.4 

5.1 

5400 

34.3 

32.4 

21.7 

13.9 

2600 

15.2 

14.4 

9.2 

5.6 

5600 

35.7 

33.7 

22.6 

14.5 

2800 

16.5 

15.6 

10.0 

6.2 

5800 

37.1 

35.0 

23.6 

15.1 

3000 

17.7 

16.8 

10.8 

6.6 

6000 

38.5 

36.3 

24.6 

15.7 

: 

TABLE    D. 


Barometrical 
Height. 

Metres. 

Barometrical 
Height. 

Metres. 

1 

15.75 

1.71 

23.62 

0.63 

17.72 

1.39 

25.59 

0.42 

19.68 

1.11 

27.56 

0.22 

21.65 

0.86 

29.53 

0.03 

| 

CHAPTER    II 
SURVEY. 


TOPOGRAPHICAL    SKETCHING. 

39.    TOPOGRAPHICAL  drawing  includes  any  thing  relating 
to  an  accurate  representation  upon  paper,  of  any  piece  of 
ground.     The  state  of  cultivation,  roads,  town,  county,  and 
state  boundaries,  and  all  else  that  occurs  in  nature.     The 
Fig.  13.  sketching  necessary  in  railroad 

surveying,  however,  does  not 
embrace  all  of  this,  but  only  the 
delineation  of  streams  and  the 
undulations  of  ground  within 
that  limit  which  affects  the  road, 
perhaps  500  feet  on  each  side  of 
the  line.  The  making  of  such 
sketches  consists  in  tracing  the 
irregular  lines  formed  by  the  in 
tersection  of  the  natural  surface, 
by  a  system  of  horizontal  planes, 
at  a  vertical  distance  of  five,  ten, 
fifteen,  or  twenty  feet,  according 
to  the  accuracy  required. 

40.  Suppose  that  we  wish  to 
represent  upon  a  horizontal  sur 
face  a  right  cone.  The  base  m 
m,  fig.  13,  is  shown  by  the  circle 


SURVEY. 


25 


of  which  the  diameter  is  w,  m.  If  the  elevation  is  cut  by 
the  horizontal  planes  a  a,  b  b,  c  c,  the  intersection  of  these 
planes  with  the  conical  surface  is  shown  by  the  circles  #,  b, 
c,  in  plan.  The  less  we  make  the  horizontal  distances,  on 
plan,  between  the  circles,  the  less  also  will  be  the  vertical 
distance  between  the  planes. 

Wishing  to  find  the  elevation  of  any  line  which  exists  on 
plan,  as  1,  2,  3,  3,  2,  1,  we  have  only  to  find  the  intersection 
of  the  verticals  drawn  through  the  points  1,  2,  3,  3,  2,  1, 
and  the  elevation  lines  a  a,  bb,  rig.  i4. 

c  c ;    this  gives  us  the  curve  4, 
5,  6,  7,  6,  5,  4. 

41.  Again,    in    fig.    14,    the 
cone  is    oblique,  which   causes 
the  circles  on  plan  to  become 
eccentric  and  elliptic.     Having 
given  the  horizontal  line  mmm, 
as  before,  we  find  it  upon  the 
elevation  in  the  same  manner. 

42.  In  the  section  of   regu 
lar   and   full    lined  figures,  the 
horizontal   and   vertical   projec 
tions  are  also  regular  and  full 
lined ;   but  in  a  broken  surface 
like  the   ground,  the   lines   be 
come  quite  irregular. 

Suppose   we   wish   to    show 
on  plan  the   hill  of  which  we 

3 


26 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


have  the  plan,  fig.  15,  and  the  sections  figs.  16,  17,  and  18. 

Fig.  15. 


Fip 


Let  A  D  be  the  profile  (made  with  the  land)  of  the  line  A  D 

on  plan,  fig.  15.  B  E  that  of 
B  E,  and  C  F  that  of  C  F. 

To  form  the  plan  from  the 
profiles  proceed  as  follows :  — 

Intersect  each  of  the  pro 
files  by  the  horizontal  planes 
a  a,  bb,  c  c,  d  d,  equidistant 
vertically.  In  the  profile  A  D, 
fig.  18,  drop  a  vertical  on  to 

Fig.  18. 


1he  base  line  from  each  of  the  intersections  a,  6,  c,  d,  d,  c,  b, 
a.  Make  now  A  1, 1  2,  2  3,  3  4,  etc.,  on  the  plan  equal  to  the 
same  on  the  profile.  Next  draw,  on  the  plan,  the  line  B  E, 


SURVEY.  27 

at  the  place  and  at  the  proper  angle  with  A  D ;  and  having 
found  the  distances  B  1,  1  2,  2  3,  etc.,  as  before,  transfer 
them  to  the  line  B  E  on  plan.  Proceed  in  the  same  man 
ner  with  the  line  C  F. 

The  points  aaa,  bbb,  c c c,  are  evidently  at  the  .same 
height  above  the  base  upon  the  profiles,  whence  the  inter 
sections  of  these  lines  with  the  surface  line  or  1  1  1,  2  2  2, 
333,  etc.,  on  the  plan,  are  also  at  the  same  height  above 
the  base  ;  and  an  irregular  line  traced  through  the  points 
1 1 1,  or  222,  will  show  the  intersection  of  a  horizontal 
plane,  with  the  natural  surface. 

When  as  at  A  we  observe  the  contour  lines  near  to  each 
other,  we  conclude  that  the  ground  is  steep.  And  when 
the  distances  are  large,  as  at  6,  7,  8,  we  know  that  the 
ground  falls  gently.  This  is  plainly  seen  both  on  plan  and 
profile. 

Having  now  the  topographical  sketch,  fig.  15,  we  may 

Fig.  15. 


easily   deduce    therefrom    at    any   point    a   profile.     If   we 
would  have  a  profile  of  G  E,  on  plan,  upon  an  indefinite 


28  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

line  G  E,  fig.  19,  we  set  off  G  1,  1  2,  2  3,  3  4,  etc.,  equal  to 

the  same  distances  on 
the  plan.  From  these 
points  draw  verticals 
intersecting  the  hori 
zontals  a  a,  b  b,  c  c ; 
and  lastly,  through  the 

intersections  draw  the  broken  line  (surface  line  or  profile) 
a,  6,  c,  d,  d,  c,  6,  a.  Thus  we  see  how  complete  a  knowl 
edge  of  the  ground  a  correct  topographical  sketch  gives. 

43.  Field  sketches  for  railroad  work  are  generally  made 
by  the  eye.     The  field  book  being  ruled  in  squares  repre 
senting  one  hundred  feet  each.     When  we  need  a  more  ac 
curate  sketch  than  this  method  gives,  we  may  cross  section 
the  ground  either  by  rods  or  with  the  level. 

By  making  a  very  detailed  map  of  a  survey,  and  filling 
in  with  sketches  of  this  kind,  the  location  may  be  made 
upon  paper  and  afterwards  transferred  to  the  ground. 

So  far  we  have  dealt  with  but  one  summit ;  but  the 
mode  of  proceeding  is  precisely  the  same  when  applied  to 
a  group  or  range  of  hills,  or  indeed  to  any  piece  of  ground. 

44.  As  a  general  thing,  the  intersection  of  the  horizontal 
planes  with  the  natural  surface  (contour  lines)  are  concave 
to  the  lower  land  in  depressions,  and  convex  to  the  lower 
land  on   spurs  and  elevations.      Thus  at  B  B  B  b  6,  fig.  20, 
upon  the  spurs,  we  have  the  lines  convex   to   the  stream; 
and    in    the    hollows  c  c  c,  the   lines    are    concave   to   the 
bottom. 

45.  Having    by   reconnoitre    found    approximately    the 
place  for  the  road,  we  proceed  to  run  a  trial  line  by  com 
pass.     In  doing  this  we  choose  the   apparent  best   place, 
stake  out  the  centre  line,  make  a  profile  of  it,  and  sketch  in 
the  topography  right  and  left. 


SURVEY. 

Fig.  20. 


30  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Suppose  that  by' doing  so  we  have  obtained  the  plan  and 

profile  shown  in  figs.  21  and  22,  where  A  a  a  B  is  the  pro- 

, file   of   Kcd  B,  on  the  plan.     The 

lowest   line     of  the   valley   though 

Fig.  21. 


quite  moderately  inclined  at  first,  from  A  to  C,  rises  quite 


SURVEY. 


31 


fast  from  C  to  the  summit;  and  as  the  inclination  becomes 
greater,  the  contour  lines  become  nearer  to  each  other. 

Now  that  the  line  may  ascend  uniformly  from  A  to  the 
summit,  the  horizontal  distances  between  the  contour  lines 
must  be  equal ;  this  equality  is  effected  by  causing  the  sur 
veyed  line  to  cut  the  contours  square  at  1,  2,  3,  4,  and 
obliquely  at  O,  8,  10.  Thus  we  obtain  the  profile  A  5  5  B. 

46.  Having  given  the  plan  arid  profile,  figs.  23  and  24, 
where  A  C  D  B  represents  the  bed  of  the  stream,  in  profile, 

Figs.  23  and  24. 


if  it  were  required  to  put  the  uniformly  inclined  line 
A  m  m  B,  upon  the  plan,  we  should  proceed  as  follows. 
Take  the  horizontal  distance  Am  from  the  profile,  and  with 


32  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

A  (on  plan)  as  a  centre,  describe  the  arc  1,  3.  The  point 
m  on  the  profile  is  evidently  three  fourths  of  a  division 
above  the  bed  of  the  stream.  So  on  the  plan  we  must 
trace  the  arc  1,  3,  until  we  come  to  #,  which  is  three  fourths 
of  b  c,  from  b.  Again,  ml  is  nine  and  one  half  divisions 
above  m.  From  a,  with  a  radius  mn  on  profile,  describe 
the  arc  4,  5,  6.  Now,  as  on  the  profile,  in  going  from  m  to 
m1,  we  cross  nine  contour  lines,  and  come  upon  the  tenth 
at  m\  so  on  the  plan  we  must  cross  nine  contour  lines  and 
come  upon  the  tenth,  and  at  the  same  time  upon  the  arc 
4,  5,  6. 

Proceeding  in  this  way,  we  find  A,  &,  &,  B,  on  the  plan, 
as  corresponding  to  A  m  m1  B  on  the  profile. 

To  establish  in  this  manner  any  particular  grade,  we 
have  first  to  place  it  upon  the  profile,  and  next  to  transfer 
it  to  the  plan. 

47.  It  may  be  remembered  as  a  general  thing,  that  the 
steepest  line  is  that  which  cuts  the  contour  line  at  right 
angles;  the  contour  line  itself  is  level,  and  as  we  vary  be 
tween  these  limits  we  vary  the  incline. 

GENERAL  ESTABLISHMENT  OF  GRADES. 

48.  Considerable   has   been   written    upon    the   relation 
which  ought  to  exist  between  the  maximum  grade,  and  the 
direction  of  the  traffic.      Some  have  given  formulae  for  ob 
taining  the  rate  and  direction  of  inclines  as  depending  upon 
the  capacity  of  power.     This  seems  going  quite  too  far,  as 
the  nature  of  the  ground   and   of  the   traffic  generally   fix 
these  in  advance. 

49.  Between  two  places  which  are  at  the  same  absolute 
elevation,  there  should  be  as  little  rise  and  fall  as  possible. 

50.  Between  points   at  different   elevations,  we   should 
if  possible  have  no  rise  while  descending,  and  consequently 
no  fall  while  on  the  ascent. 


SURVEY.  33 

51.  Some   engineers   express  themselves  very  much  in 
favor  of  long  levels  and  short  but  steep  inclines.     There 
are  cases  where  the  momentum  acquired  upon  one  grade, 
or  upon  a  level,  assists  the  train  up  the  next  incline.     The 
distance  on  the  rise  during  which  momentum  lasts,  is  not 
very  great     A  train  in  descending  a  plane  does  not  receive 
a  constant  increase  of  available  momentum,  but  arrives  at  a 
certain  speed,  where  by  increased  resistance  and  by  added 
effect  of  gravity,  the  motion  becomes  nearly  regular.     Up 
to  this  point  the  momentum  acquired  is  useful,  but  not  be 
yond. 

Any  road  being  divided  into  locomotive  sections,  the  sec 
tion  given  to  any  one  engine  should  be  such  as  to  require  a 
constant  expenditure  of  power  as  nearly  as  possible ;  i.  e., 
one  section,  or  the  run  of  one  engine,  should  not  embrace 
long  levels  and  steep  grades.  If  an  engine  can  carry  a  load 
over  a  sixty  feet  grade,  it  will  be  too  heavy  to  work  the 
same  load  upon  a  level  economically.  It  is  best  to  group 
all  of  the  necessarily  steep  grades  in  one  place,  and  also  the 
easy  portions  of  the  road ;  then  by  properly  adapting  the 
locomotives  the  cost  of  power  may  be  reduced  to  a  min 
imum. 

As  to  long  levels  and  short  inclines  the  same  power  is  re 
quired  to  overcome  a  given  rise,  but  quite  a  difference  may 
be  made  in  the  means  used  to  surmount  that  ascent. 

52.  Suppose  Ve  have  the  profiles  A  E  D  and  A  B  D,  fig. 
25.    The  resist- 

ance  from  A  to 
D  by  the  con 
tinuous  twenty 
feet  grade  is 
the  same  as 
the  whole  re 
sistance  from  A  to  B  and  from  B  to  D.  The  reason  for 


34  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

preferring  A  E  D  is,  that  an  engine  to  take  a  given  load 
from  B  to  D  would  be  unnecessarily  heavy  for  the  section 
A  B ;  while  the  same  power  must  be  exerted  at  each  point, 
of  A  E  D.  Also  the  return  by  A  E  D  is  made  by  a  small 
and  constant  expenditure  of  power,  being  all  of  the  way 
aided  by  gravity ;  while  in  descending  by  B,  we  have  more 
aid  from  gravity  than  we  require  from  D  to  B,  after  which 
we  have  none. 

When  the  distances  A  B,  B  C,  are  sixty  and  twenty 
miles  in  place  of  six  and  two,  we  may  consider  the  grades 
grouped  at  B  D,  and  use  a  heavier  engine  at  that  point,  as 
we  should  hardly  find  eighty  miles  admitting  of  a  continu 
ous  and  uniform  grade. 

EQUATING   FOR    GRADES. 

53.  In  comparing  the  relative  advantages  of  several  lines 
having  different  systems  of  grades,  it  is  customary  to  re 
duce  them  all  to  the  level  line  involving  an  equal  expendi 
ture  of  power. 

The  question  is  to  find  the  vertical  rise,  consuming  an 
amount  of  power  equal  to  that  expended  upon  the  horizon 
tal  unit  of  length.  This  has  been  estimated  by  engineers 
all  the  way  from  twenty  to  seventy  feet.  For  simple  com 
parison  it  does  not  matter  much  what  number  is  used  if  it 
is  the  same  in  all  cases ;  but  to  find  the  equivalent  horizon 
tal  length  to  any  location,  regard  must  be  had  to  the  nature 
of  the  expected  traffic. 

The  elements  of  the  problem  are,  the  length,  the  inclina 
tion  or  the  total  rise  and  fall,  and  the  resistance  to  the  mo 
tion  of  the  train  upon  a  level,  which  latter  depends  upon 
the  speed  and  the  state  of  the  rails  and  machinery. 

From  chapter  XIV.  we  have  the  following  resistances  to 
the  motion  of  trains  upon  a  level :  — 


SURVEY.  35 

Velocity,  in  miles,  per  hour.  Resistance,  in  Ibs.  per  ton. 

10  8.6 

15  9.3 

20  10.3 

25  11.6 

30  13.3 

40  17.3 

50  22.6 

CO  27.1 

100  66.5 

The  power  expended  upon  any  road  is  of  course  the 
product  of  the  resistance  per  unit  of  length,  by  the  number 
of  units.  Calling  R  the  resistance  per  unit  upon  a  level, 
and  R  the  resistance  per  unit  on  any  grade,  and  desig 
nating  the  lengths  by  L  and  Z/,  that  there  shall  be  in  both 
cases  an  equal  expenditure  of  power,  we  must  have 


whence  the  level  length  must  be 


Thus  assuming  the  resistance  on  a  level  as  twenty  Ibs. 
per  ton,  that  on  a  fifty  feet  grade  is 

20  +  rfifo  of  2240,  or  20  +  21.2  or  41.2, 

and  if  the  length  of  the  inclined  line  is  ten  miles,  the  equiva 
lent  level  length  is 

41.2  X  52800 
L  = 2Q—    ~  ==  108768  feet>  or  20-6  miles. 

Also  10  miles  X  41.2  Ibs.  =412, 
and  20.6    «     X  20      «    =  412. 


36  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

54.  The  above  may  be  somewhat  abridged  as  follows : 
Let  R  be  the  resistance  on  a  level.  The  resistance  due  to 
any  grade  is  expressed  by 


where  -  is  the  fraction  showing  the  grade,  and  IF  the  weight 

of  the  load. 

The  vertical  height  in  feet,  to  overcome  which  we  must 
expend  an  amount  of  power  sufficient  to  move  the  train 
one  mile  on  a  tevel,  must  be  such  that 


or 

1_72 

a~  W' 

and  to  find  the  number  by  which  to  equate,  we  have  only  to 
place  the  values  of  R  and  TFin  the  formula.  For  example, 
let  the  speed  be  twenty  miles  per  hour,  the  corresponding 
resistance  is  10.3  Ibs.  per  ton.  W  being  one  ton,  or  2240 
Ibs.,  we  have 


1          -p        103  1 

±  —  —  —  —  —  -^-  of  5280,  (the  number  of  feet  in  one  mile,) 

a       W      2240       21o 

J_  of  5280  =  24  feet. 
218 

In  the  same  manner  we  have 

Speed,  in  miles,  per  hour.  Equating  number. 

15  22 

20  24 

30  32 

40  41 

50  53 

60  67 

100  155 


SURVEY.  37 

Thus  when  we  take  the  speed  as  thirty  miles  per  hour, 
for  each  thirty-two  feet  rise  we  shall  consume  an  amount  of 
power  sufficient  to  move  the  train  one  mile  on  a  level.  In 
descending,  the  grade  instead  of  being  an  obstacle,  becomes 
an  aid ;  indeed  the  incline  may  be  such  as  to  move  the 
trains  independently  of  the  steam  power.  Thus  if  on  ac 
count  of  ascending  grades  we  increase  the  equated  length, 
so  also  in  descending  we  must  reduce  the  length.  The 
amount  of  reduction  is  not,  however,  the  reverse  of  the  in 
crease  in  ascending,  as  after  thirty  or  forty  feet  any  addi 
tional  fall  per  mile  instead  of  being  an  advantage  is  an 
evil ;  as  too  much  gravity  obliges  us  to  run  down  grades 
with  brakes  on.  Twenty-five  feet  per  mile  is  sufficient  to 
allow  the  train  to  roll  down,  and  any  more  than  this  is  of 
very  little  use.  Therefore  for  every  mile  of  grade  descend 
ing  at  the  rate  of  twenty-five  feet  per  mile  we  may  deduct 
one  mile  in  equating,  and  for  every  mile  of  grade  descend 
ing  twelve  and  one  half  feet  per  mile  deduct  a  proportional 
amount ;  but  for  any  more  fall  per  mile  than  twenty-five  feet, 
no  allowance  should  be  made ;  i.  e.,  if  we  descend  at  the 
rate  of  forty  feet  per  mile,  we  may  deduct  one  mile  in 
equating  for  the  twenty-five  feet  of  fall,  and  throw  aside 
the  remaining  fifteen  feet. 

55.  This  is  a  common  method  of  equating  for  grades, 
and  represents  a  length  which  is  proportional  to  the  power 
expended,  but  not  proportional  to  the  cost  of  working,  as 
the  ratios  of  power  expended  and  cost  of  working  under 
different  conditions  are  very  different,  double  power  requir 
ing  only  twenty  per  cent,  more  working  capital.  The  above 
rules,  therefore,  require  a  correction. 

The  cost  of  working  a  power  represented  by  unity  being 
expressed  by  100  ; 

That  of  working  a  power  2  is  expressed  by  125  ; 

4 


38  HANDBOOK    OF   RAILROAD    CONSTRUCTION. 

That  of  working  a  power  3  is  expressed  by  150  ; 

«  «  «       4  "          "  175  ; 

«  «  «      5  «         «  200. 

(See  Appendix  F.) 

Now  the  resistance  on  a  level  being  at  a  velocity  of  twenty 
miles  per  hour,  10.3  Ibs.  per  ton  by  the  formula 


the  vertical  height  in  feet  causing  a  double  expenditure  of 
power  is  twenty-four  ;  but  as  above,  the  whole  expense  of 
a  double  power  is  increased  by  only  twenty  -five  per  cent.  ; 
we  should  not  add  one  mile  for  twenty-four  feet  rise,  but 
one  fourth  of  a  mile  only,  or  one  mile  for  each  ninety-six 
feet  ;  and  by  correcting  our  former  table  in  this  manner,  we 
have  the  following  table  :  — 

Speed,  in  miles,  per  hour.  Equating  number. 

15  88 

20  96 

25  110 

30  128 

40  164 

50  212 

60  276 

100  620 

So  much  for  equating  for  the  ascents.  In  descending,  we 
have  allowed  one  mile  reduction  for  each  mile  of  twenty- 
five  feet  of  descending  grade  ;  but  as  in  ascending  we  cor 
rect  the  first  made  table,  so  in  descending  we  must  also 
correct  as  follows.  If  we  needed  no  steam  power  either 
while  descending  or  afterwards,  we  should  only  save  wood 
and  water  ;  as  a  general  thing  the  fire  must  be  kept  up 
while  descending,  and  the  only  gain  is  a  small  part  of  the 


SURVEY.  39 

expense  of  fuel ;  so  small,  in  fine,  that  with  the  exception 
of  roads  which  incline  for  the  whole  or  a  great  part  of  their 
length,  no  reduction  should  be  made. 

COMPARISON    OF    SURVEYED    LINES. 

56.    The  requisite  data  for  an   approximate  comparison 
of  lines  are,  the  measured  length,  total  rise,  total  fall. 

Let  the  length  of  line  A  be  100  miles, 

"  «  «          JJ     «  QQ          4; 

Whole  rise  on  A  2000  feet, 

"          "      B  5100      « 

Whole  fall  on  A  1200      « 

"          "      B  4300      " 

Assume  the  number  by  which  to  equate,  as  ninety-six,  and 
we  shall  have 

Line  A. 

Ascending,    100-f-2§§-=  120.83 

Descending,  1 00  -f-  if  f  a  =  112.50 

Sum  233.33 

Mean  116.66 
Line  B. 

Ascending,    90  +  ^fl=  142.13 

Descending,  90-|-*f§4—  134.80 

Sum  276.93 

Mean  138.46 

The  mean  equated  length  of  A  is  116.66 

The  measured  length  of  A  is  100.00 

The  difference       16.66 

The  mean  equated  length  of  B  is  138.46 

The  measured  length  of  B  is  90.00 

The  difference       58.46. 


40  HANDBOOK   OF  EAILBOAD  CONSTRUCTION. 

The  cost  of  construction  being  assumed  as  the  actual 
length,  and  that  of  working  as  the  equated  length,  we  have 
the  final  approximate  comparison  thus :  — 

Assume  the  construction  cost  as  $25,000  per  mile,  and 
the  cost  of  maintenance  $4,000  per  mile,  and  we  have 

The  line  A  to  the  line  B  as 


100  X  25000  +  116.66  X  4000  X  ^  =  10310.667,  is  to 


90  X  25000  -[-  138.46  X  4000  X  ^  =  11480.667 ; 
or  A  is  to  B  as  10.3  to  11.5  nearly,  although  the  line  A  is  ten  miles 


longer  than  B. 


CHAPTER     III 


LOCATION. 


ALIGNMENT. 

57.  THE  broken  line  furnished  by  the  survey  is  of  course 
unfit  for  the  centre  line  of  a  railroad.     The  angles  require 
to  be  rounded  off  to  render  the  passage  from  one  straight 
portion  to  the  other  easy. 

58.  Let  A  X  B,  fig.  26,  represent  the  angle  formed  by 

Fig.  26. 


42  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

any  two  tangents  which  it  is  required  to  connect  by  a  circu 
lar  curve.  It  is  plain  that  knowing  the  angle  of  deflection 
of  the  lines  A  X,  B  X,  we  obtain  also  the  angles  A  C  X, 
X  C  B.  The  manner  of  laying  these  curves  upon  the 
ground  is  by  placing  an  angular  instrument  at  any  point 
of  the  curve,  as  at  A,  and  laying  off  the  partial  angles 
E  A  a,  E  A  M,  E  A  G,  etc.,  which  combined  with  the  cor 
responding  distances  A  #,  a  M,  M  G,  fix  points  in  the  curve. 

Thus  small  chords  are  generally  assumed  at  one  hundred 
feet,  except  in  curves  of  small  radius  (five  hundred  feet) 
when  they  are  taken  less. 

The  only  calculation  necessary  in  laying  out  curves,  is, 
knowing  the  partial  deflection  to  find  the  corresponding 
chord,  or  knowing  the  chord,  to  get  the  partial  angle. 

As  the  radius  of  that  curve  of  which  the  angle  of  de 
flection  is  1°  is  5730  feet,  the  degree  of  curvature  for  any 
other  radius  is  easily  found.  Thus  the  radius  2865  has  a 
degree  of  curvature  per  one  hundred  feet  of 

«f*==2°; 

again, 

f$J$=2°.81,  or  2°48'.6. 

The  radius  corresponding  to  any  angle  is  found  by  re 
versing  the  operation.  If  the  angle  is  3°  30',  or  210',  we 
have 

—  =z!637  feet  radius. 

The  following  figures  show  the  angle  of  deflection  for 
chords  one  hundred  feet  long,  corresponding  to  different 
radii :  — 


LOCATION.  43 

Angle  of  deflection.  Radius,  in  feet. 

£°  or  15'  22920.0 

y  or  30'  11460.0 

|°  or  45'  7640.0 

1°  or  60'  5730.0 

1J°  4585.0 

H°  3820.0 

1|°  3274.0 

2°  2865.0 

2i°  2292.0 

3°  1910.0 

3i°  1637.0 

4°  1433.0 

4£°  1274.0 

5°  1146.0 

5J°  1042.0 

6°  955.4 

6J°  822.0 

7°  819.0 

i  764.5 


° 


716.8 


10°  573. 


Points  in  any  curve  may  also  be  fixed  by  ordinates,  as  a  b, 
M  D',  G  F,  or  by  E  a,  K  M,  etc. 

For  the  details  of  locating,  of  running  simple  and  corn- 
pound  curves,  and  of  the  calculations  therefor,  the  reader  is 
referred  to  the  works  of  Trautwine,  and  of  Hencke. 


44 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 
Fig.  27. 


LOCATION, 


45 


59.  Suppose    now  that 
we  have  the  surveyed  lines 
m  m,  and  n  n,  fig.  27,  one 
of  which  is  to  be  finally 
adjusted    to    the   ground. 
The   shortest   line   is   the 
straight  one,  which  is  gen 
erally  impracticable.     The 
most  level  line  is  the  con 
tour    line,   which  is    also 
impracticable.       Between 
these    two   lies   the   right 
line,  which  is  to  be  found 
by  an  instrumental   loca 
tion.      The  line  Annnn 
B,  on  the  plan,  gives  the 
profile    A.nnnnl3.      The 
line    A  m  m  m  m  B   gives 
the  profile  A  m  m  m  m  B, 
while  the  finally  adjusted 
line  A 1  2  3  4  5  6  gives  the 
profile  A123456B. 

60.  Again,   in   fig.   28, 
the  straight  line  A  n  n  n  B 
gives  the  profile  A  n  n  n  B, 
requiring       either      steep 
grades  or  a  great  deal  of 
work.     By  fitting  the  line 
to  the  ground,  as  by  the 
line  Aab  cd  .  .  .mwoB, 
we  obtain  the  profile  A  a 
b  c  .  .  .  m  n  o  B. 


Fig.  28. 


46 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FINAL    ADJUSTING    OF    GRADES. 

Fig.  29.  61.    The    general    arrangement    of 

inclines  must  not  be  interfered  with 
to  save  work,  but  a  large  part  of  the 
excavation  and  embankment  may  be 
saved  by  breaking  up  long  grades  so 
as  not  to  affect  materially  the  charac 
ter  of  the  road.  Upon  some  lines  the 
grades  must  necessarily  undulate,  as 
in  fig.  29.  The  difference  in  the 
amount  of  work  is  plainly  seen.  The 
steepest  grades  thus  applied  must  not 
be  greater  than  the  ruling  grade  upon 
the  travel  of  one  engine. 

62.  In  long  and  shallow  cuts  and 
fills,  the  best  plan  is  to  place  the  grade 
line   quite   high,  avoiding  much   cut 
ting,  and  to  make  the  embankments 
from  side  cuttings,  (ditching).    Banks 
must  at  least  be  placed  two  or  three 
feet  above  the  natural  surface,  first  to 
prevent  the    snow  from   lodging   too 
much  upon  the  rails,  second,  to  insure 
draining. 

63.  Snow  fences  are  much  used  in 
the    northern    parts    of    the    United 
States.     These  are  high  pieces  of  lat 
tice-work,    made    roughly,   but    well 
braced ;  from  eight  to  twelve  feet  high, 
and  standing  from  sixty  to   one  hun 
dred  feet  from  the  road.     The  object 
of  the  fence  is  to  break  the  current  of 


LOCATION.  47 

the  wind,  and  cause  it  to  precipitate  its  snow.  Close  fences 
effect  the  object  no  better  than  the  open  ones,  are  more  lia 
ble  to  blow  down,  and  cost  more. 

64.  In  locating  a  road  which  is  to  have  a  double  track 
eventually,  regard  must  be  paid  to  this  fact  in  side-hill  work. 
The  first  track  should,  if  possible,  be  so  placed  as  not  to  re 
quire  moving  when  the  double  line  is  put  on. 


COMPARISON    OF    LOCATED    LINES. 

65.  In  this  comparison  there  is  an  element  which  does 
not   enter  the  approximate  comparison  of  surveyed  lines, 
curvature.    The  resistance  arising  from  this  cause  has  never 
been  accurately  determined.     Mr.  McCullurn  estimates  the 
resistance  at  one   half  pound  per  degree  of  curvature  per 
one  hundred  feet ;  i.  e.,  the  resistance  due  to  curvature  on  a 
4°  curve,  would  be  two  Ibs.  per  ton,  (see  report  of  Septem 
ber  30,  1855).     Mr.  Clark  estimates  the  resistance  due  to 
curves  of  one  mile  radius  and  under,  as  6.3  Ibs.  per  ton,  or 
twenty  per  cent,  of  the  whole  distance.     The  average  ra 
dius  encountered,  therefore,  by  Mr.  Clark,  would  be,  at  Mr. 
McCullum's  estimate, 

6.3 

-T—^  =  12°  nearly,  or  477.5  feet. 

So  small  a  radius  is  by  no  means  allowable  upon  English 
roads;  thus  the  estimate  of  Mr.  Clark  and  of  Mr.  McCul- 
lum  differ  considerably.  Experiments  might  easily  be  made 
with  the  dynamometer  upon  different  curves,  by  which  we 
might  find  very  nearly  the  correct  resistance  caused  by 
curves. 

The  curvature  on  any  road  cannot  be  adjusted  to  trains 
moving  at  different  speeds. 

66.  The  tractive  power  acts  always  tangent  to  the  curve 


48  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 

at  the  point  where  the  engine  is,  and  thus  tends  to  pull  the 
cars  against  the  inner  rail.  The  tangential  force,  generated 
by  the  motion  of  the  cars,  tends  to  keep  the  flanges  of  the 
wheels  against  the  outer  rail ;  and  only  when  a  just  balance 
is  made  between  the  tractive  and  tangential  forces,  the 
wheel  will  run  without  infringing  on  either  rail,  (the  wheel 
being  properly  coned).  For  these  forces  to  balance,  there 
must  be  a  fixed  ratio  between  the  weight  of  a  car  and  the 
speed,  (not  the  weight  of  a  train,  as  the  slacking  allows  the 
cars  to  act  nearly  independently,  some  indeed  rubbing  hard 
for  a  moment  against  the  rail,  while  the  next  car  is  work 
ing  at  ease).  Whenever  the  right  proportion  is  departed 
from,  as  it  nearly  always  is,  (and  perhaps  necessarily  in 
some  cases,)  upon  railroads,  the  wheels  will  rub  against  one 
rail  or  the  other.  Thus  on  any  road  where  the  speed  on 
the  same  curve,  or  the  radii  of  curvature  under  the  same 
speed,  differ,  there  must  be  loss  of  power,  and  dragging  or 
pushing  against  the  rails. 

67.  We  are  obliged  to  elevate  the  outer  rail  (see  chapter 
XIII.),  for  the  fastest  trains,  and  the  slower  trains  on  such 
roads  will  therefore   always  drag   against  the  inner  rails. 
Thus  in  practice  we  generally  find  the  inside  of  the  outer 
rail  most  worn  on  passenger  roads,  and  the  inside  of  the 
inner  rail  upon  chiefly  freight  roads. 

68.  It  has  been  the  practice  of  some  engineers  in  equat 
ing  for  curvature,  to  add  one  fourth  of  a  mile  to  the  meas 
ured  length  for  each  360°  of  curvature,  disregarding  the  ra 
dius,  as  the  length  of  circumference  increased  inversely  as 
the  degree  of  curvature. 

69.  Now  in  equating  for  grades,  in  doubling  the  power 
we  do  not  double  the  expense  of  working.     We  however 
increase  it  more  by  curvature  than  we  do  by  grades,  be 
cause  besides  requiring  double  power,  the  wear  and  tear  of 
cars  and  rails  and  all  machinery  is  increased  upon  curves, 
which  is  not  the  case  upon  grades. 


LOCATION.  49 

70.    The  analysis  of  expense  (in  Appendix  F.)  upon  the 
New  York  system  of  roads,  gives  the  following  :  — 

Locomotives,  40  per  cent. 

Cars,  20    "      " 

Way  and  works,  15    u      " 

or  in  all,  75  per  cent. 


Now  each  360°  will  be  equal  to  TVfr  of  one  quarter  of  a 
mile,  or  47o5o  of  a  mile  ;  whence  the  number  of  degrees 
which  shall  cause  an  expense  equal  to  one  straight  and 
level  mile,  will  be  1920°. 

71.  The  number  of  degrees  by  Mr.  McCullum's  estimate 
would  be  thus  :  — 

The  resistance  upon  a  level  being  ten  Ibs.  per  ton,  and 
that  due  to  curves  one  half  pound  per  ton,  per  degree  per 
one  hundred  feet  ;  the  length  of  a  2°  curve  to  equal  one 
mile  will  be 

10  Ibs. 
lib.  ' 

or  ten  miles.  Also  ten  miles,  or  530  hundred  feet  by  2° 
is  1060°. 

72.  Again,  by  Mr.  Clark's  resistance  of  twenty  per  cent. 
of  the  level  resistance,  upon  curves  averaging  2°,  we  have 
as  the  length  of  2°  curve 

-TT  =  5  miles, 
jf 

or  265  hundred  feet,  which  by  2°  gives  530°. 

73.  Averaging  the  first  and  last,  we  have  as  the  number 
of    degrees   which   should    be   considered   as   causing   an 
amount  of  expense  equal  to  one  straight  and  level  mile, 
1225°,  which  averaging  with  the  estimated  resistance  by 
Mr.  McCullum,  gives  finally  1142J0  as  causing  an  expense 

5 


50  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

equal  to  one  straight  and  level  mile,  or,  in  round  numbers, 
1140°. 

74.    Suppose  now  that  we  would  know  which  of  the  lines 
below  to  choose. 


Line  A. 

Line  B. 

Description. 

100  miles, 

110  miles, 

Actual  length, 

5000  feet, 

.    3000  feet, 

Rise, 

3500     " 

1500     " 

Fall, 

3600°  9000°  Decrees  of  curvature 


o 


Assuming  the  speed  as  twenty  miles  per  hour,  the  num 
ber  by  which  to  equate  for  grades,  see  chapter  II.,  is  nine 
ty-six,  also  the  number  of  degrees  for  curvature  1140, 
whence, 

Line  A  ascending  100  +  52.1  +  3.16  =  155.26  ) 

(  147  A(\ 
Line  A  descending  100 +  36.5 +3.16  =  139.66  ) 

Line  B  ascending  110  +  31.25  +  7.89  =  149.14  ) 

Line  B  descending  110  +  15.60  +  7.89  —  133.49  j  14L31> 

and  if  the  cost  of  construction  is  as  the  actual,  and  the  cost 
of  maintaining  and  working  as  the  mean  equated  length, 
we  have,  as  a  final  comparison, 

A  to  B  as  100  +  147.46  to  110  +  141.31, 

or  as 

247.46  to  251.31. 

Here  the  extra  grades  on  the  one  hand  nearly  equal  the 
curvature  and  the  extra  length  on  the  other  hand. 

75.  As  a  further  example  in  the  comparison  of  compet 
ing  lines,  let  us  take  the  actual  case  of  the  location  of  the 
eastern  part  of  the  New  York  and  Erie  Railroad. 

It  was  questioned  which  of  the  two  lines  between  Bing- 
hampton  and  Deposit  should  be  adopted,  and  also  between 
the  mouth  of  Callicoon  Creek  and  Port  Jervis. 


LOCATION. 


51 


Between  A 
and  c,  fig. 
30,  were  lo 
cated  the  lines 
shown  in  the 
sketch ,  one 
following  the 
Snsquehanna 
river  from  A 
to  B,  thence 
crossing  the 
dividing  ridge 
between  that 
river  and  the 
Delaware  to 
Deposit  (c). 
The  other 
passing  up  the 
Chen  an  go  riv 
er  to  &,  thence 
crossing  first 
the  summit 
M  to  the  Sus 
quehanna  at 
L,  and  second 
the  summit  K, 
to  Deposit  (c). 
The  elements 
of  the  two  lines  are  as  follows :  — 


Fig.  30. 


52  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

A  route,  A  B  c.  B  route,  A  M  K  c. 

Length,                              39.29  43.58 

Rise  A  to  c,                    540.00  1087.00 

Rise  c  to  A,                     395.00  936.00 

Whole  rise  and  fall,         935.00  2023.00 

Degrees  of  curvature,  2371°.00  3253°.00 

Estimated  cost,        $746,900.00  $628,600.00. 

Assuming  the  number  by  which  to  equate  for  grades,  as 
96,  and  the  equating  number  of  degrees  of  curvature  as 
1140°  ;  equating  for  grades  and  curvature  in  both  directions, 
we  have, 


Route  A.    A  to  c. 

KAf)  9371 

39.29  +  —  +  — —  =  39.29  +  5.63  +  2.08  =  47.00 
y  o       JL  JL  ~LU 

Route  A.    c  to  A. 

39.29  +  —  +  —  =  39.29  +  4.12  +  2.08  =  45.59 
y  b        1  -L  4U 

Route  B.     A  to  c. 
43.58  +  ^  +  5||?  =  43.58  +  1132  +  2.85  =  57.75 

Route  B.     c  to  A. 
43.58  +  5  +  TT§  =  43'58  + 


Mean, 
46.25. 


Mean, 
56.96. 


Assuming  the  cost  of  working  and  of  maintaining  as 
$4,000  per  mile,  we  have 

The  cost  of  building  A  to  B  as  $746,900  to  $628,600 
The  cost  of  operating  A  to  B  as  (46.25  X  4000)  X  *F  to 
(56.96  X  4000)  X  AF> 

or  as  $3,083,334  to  $3,797,334 

and  the  sum  as  $3,830,234       $4,425,934 


LOCATION. 


53 


giving  the  preference  of  $595,700  to  the  route  A  B  c,  not 
withstanding  that  the  estimate  thereon  exceeds  that  on  B 
by  $118,300.  The  route  A  B  c  was  adopted. 

Again,  it  was  doubtful  whether  to  adopt  the  route  E  F, 
in  going  from  D  to  G,  or  the  line  I  H.  The  following  are 
the  elements  of  the  two  lines :  — 


IH. 

EF. 

Measured  length, 

61.14 

58.53 

Rise  D  to  G, 

1187 

454 

Rise  G  to  D, 

1049 

316 

Degrees  curve, 

7609° 

4588° 

Estimated  cost, 

$1,094,950 

$1,496,430. 

The  mean  equated  lengths  are  as  follows  :  — 
Line  I  H.     D  to  G. 


61.14  + 


=  61.14  +  12.36  +  6.68  =  80.18 


Line  I  H.     G  to  D. 
1049   .   7609 


1140 


=  61.14  -f  10.93  +  6.68  =  78.75 


Mean, 
79.46, 


Line  E  F.     D  to  G. 

4588 


=  58.53  -j-  4.73  -f  4.02  =  67.28 


58.53  + 


58.53  +        +  =  58.53  +  3.29  +  4.02  =  65.84 


1140 
Line  E  F.     G  to  D. 


Mean, 
66.56. 


The  comparison  as  to  cost  is 

I  H  to  E  F  as  $1,094,950  to  $1,496,430, 
and  as  to  working, 

I H  to  E  F  as  (79.46  X  4000)  X  H*  to  (66.56  X  4000)  X 

5* 


54  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

and  the  sum  as 

1,094,950  to     1,496,430 
,297.334     +  4,437.334 


or   $6,392,284  to   $5,933,764. 

Although  the  cost  of  E  F  is  $401,480  more  than  that  of 
I  H,  the  line  E  F  was  adopted. 


CHAPTER  IV. 

PRELIMINARY  OPERATIONS. 


0 


SPECIFICATION. 

76.  THE  object  of  this  paper  is  to  define  exactly  the  terms 
of  the  contract  as  regards  execution  of  work.  Every  thing 
therein  should  be  expressed  in  a  manner  so  plain  as  to  leave 
no  room  for  misunderstanding. 

The  following  has  the  approval  of  the  best  engineers :  — 

i 

A   AND   B   RAILROAD. 

77.    Specification  for    Graduation. 
LINE. 

The  centre  of  the  road-bed  to  conform  correctly  to  the  cen 
tre  line  of  the  railroad,  as  staked  out  or  otherwise  indicated 
on  the  ground,  and  to  its  appropriate  curvatures  and  grades 
as  defined  and  described  by  the  engineer;  and  the  con 
tractor  shall  make  such  deviations  from  these  lines  or  grades 
at  any  time,  as  the  said  engineer  may  require.  The  road 
bed  to  conform  to  the  cross  section  which  shall  be  given  or 
described,  or  to  such  other  instructions  as  may  be  given  as 
hereinafter  limited ;  and  the  same  of  the  ditches  and  slopes 


56  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

of  the  work,  and  of  all  operations  pertinent  to  the  satisfac 
tory  performance  of  the  graduation  or  masonry  on  the  part 
or  parts  of  the  line  contracted  for. 


CLEARING. 

The  ground  forming  the  base  of  all  embankments,  and 
five  feet  beyond  the  foot  of  the  slopes  of  all  embankments, 
to  be  cleared  as  close  to  the  surface  as  practicable,  of  all 
timber,  saplings,  brush,  logs,  stumps,  or  other  perishable 
material.  The  valuable  timber  to  be  laid  aside,  beyond  the 
clearing  as  directed  by  the  engineer,  the  rest  to  be  burned, 
if  this  can  be  done  safely,  otherwise  to  be  moved  beyond 
the  limits  of  the  cleared  ground.  The  ground  for  ten  feet 
beyond  the  top  lines  of  all  slopes  of  cuttings  shall  be  cleared 
in  like  manner,  of  all  timber  and  saplings.  Wherever  ad 
ditional  ground  has  to  be  taken  in  widening  excavations  to 
obtain  materials,  or  in  widening  embankments  to  dispose  of 
surplus  material,  or  in  grading  for  turnouts  or  depot  grounds, 
an  additional  amount  of  ground  shall  be  cleared  in  like  man 
ner;  and  when  directed  by  the  engineer,  wherever  addi 
tional  space  is  required  for  outside  ditching,  or  for  altera 
tions  of  roads  or  watercourses,  or  otherwise. 


GRUBBING. 

All  stumps  and  large  roots  within  ten  feet  of  the  grade 
line  shall  be  grubbed  out  to  the  entire  width  of  the  work, 
and  moved  at  least  ten  feet  beyond  the  slopes.  The  cost 
of  all  clearing  and  grubbing  is  included  in  the  price  for 
earth  work,  which  price  is  also  understood  to  include  all 
clearing  and  grubbing  necessary  in  borrowing  pits,  spoil 
banks,  road  crossings,  alterations  of  roads  and  watercourses, 


SPECIFICATION.  57 

the  formation  of  ditches  or  otherwise.  The  necessary  clear 
ing  and  grubbing  in  all  cases  to  be  kept  completed  five 
hundred  feet  in  advance  of  any  work  in  progress. 


MUCKING. 

Wherever  mud,  muck,  or  similar  soft  material  occurs  in 
excavations  or  embankments,  within  two  feet  of  subgrade, 
it  shall  be  removed  and  replaced  by  compact  earth  or  gravel. 

GRADE. 

The  grade  lines  on  the  profiles  show  the  true  grade,  and 
correspond  with  a  line  two  inches  below  the  bottom  of  the 
iron  rail  of  the  superstructure.  What  is  called  subgrade 
corresponds  with  a  line  placed  eighteen  inches  below  the 
grade.* 

WIDTH   OF  ROAD,   AND    SLOPES. 

The  width  of  road- way,  unless  otherwise  directed,  shall 
be  twenty-two  feet  wide  at  grade  in  earth  excavations,  and 
eighteen  feet  wide  in  rock  excavations.  Both  rock  and 
earth  shall  be  taken  out  eighteen  inches  below  grade  for 
the  entire  width  of  road-way.  The  bottoming  to  be  re 
placed  by  gravel,  broken  stone,  or  spawls,  in  such  manner  as 
shall  be  directed  by  the  engineer,  leaving  the  necessary 
ditches  of  the  width  and  depth  directed  on  either  side. 
The  contractor  will  not  be  paid  for  any  rock  excavated  be 
yond  the  slope  lines  of  one  to  eight  from  the  required  width, 
or  for  any  earth  excavated  beyond  slope  lines  of  one  and 


*  The  distance  between  grade  and  subgrade  depends  somewhat  upon 
the  climate,  but  is  generally  between  one  and  two  feet.     See  chap.  XIII. 


58  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

one  half  horizontal  to  one  vertical,  unless  directed  by  the 
engineer  to  move  additional  rock  or  earth. 


BLASTING. 


All  blasting  shall  be  done  at  the  risk  of  the  first  party, 
who  shall  be  liable  to  the  second  parties,  or  to  the  railroad 
company,  for  any  damages  incurred  in  consequence,  to 
dwelling-houses,  individuals,  or  otherwise. 


DITCHES. 

Whenever  required,  ditches  shall  be  cut  along  the  tops  of 
the  slopes,  of  the  form  of  size  and  in  the  position  directed. 

SURPLUS    MATERIAL. 

Whenever  the  earth  or  rock  required  for  the  adjoining 
embankments  exceeds  the  amount  in  the  neighboring  exca 
vations,  the  contractor,  when  required,  shall  increase  the 
width  of  said  excavations,  as  directed  by  the  engineer,  to  a 
sufficient  width  for  a  double  track,  provided  that  this  addi 
tional  width  shall  not  be  extended  so  as  to  produce  an  aver 
age  haul  of  more  than  eight  hundred  lineal  feet,  on  said 
borrowed  stuff.  And  whenever  the  earth  or  rock  to  be 
moved  from  any  cut  exceeds  in  amount  the  adjoining  em 
bankments,  (unless  elsewhere  wanted,)  it  shall  be  applied  to 
widening  the  embankment  to  a  width  for  a  double  track, 
within  the  same  limits  of  haul ;  but  for  a  greater  haul  than 
eight  hundred  feet,  the  contractor  shall  be  paid  one  cent  per 
yard  per  hundred  feet  of  excess. 

BORROW  PITS. 

Where  the  excavation  does  not  furnish  sufficient  material 
to  make  the  adjoining  embankments,  borrow  pits  may  be 


SPECIFICATION.  59 

opened.  But  no  earth  shall  be  deposited  in  spoil  banks  nor 
borrow  pits  opened  without  the  knowledge  and  consent  of 
the  superintending  engineer,  who  shall  take  care  that  such 
operations  are  arranged  so  as  not  to  damage  the  road  or  its 
slopes,  nor  interfere  with  the  widening  of  the  road-bed  at  a 
future  time  for  additional  tracks. 

MATERIAL    TO    BE    SAVED. 

If  materials  be  found  in  the  excavations  applicable  to 
useful  purposes,  such  as  building  stone,  limestone,  gravel, 
minerals,  etc.,  they  shall  be  laid  aside  in  such  place  as  the 
engineer  may  direct,  for  use,  to  be  applied  then  or  subse 
quently  to  the  construction  of  the  road  under  the  conditions 
of  these  specifications  and  of  the  contract. 

CLASSIFICATION    OF   MATERIALS. 

Earth  —  every  thing  except  solid  and  loose  rock.  Loose 
rock  —  all  boulders  and  detached  masses  of  rock  measuring 
over  one  cubic  foot  in  bulk  and  less  than  five  cubic  yards. 
Solid  rock,  includes  all  work  in  ledge,  which  requires  drill 
ing  and  splitting,  and  all  loose  rocks  containing  more  than 
five  cubic  yards. 

The  prices  for  excavation  include  all  earth  or  rock  exca 
vated  in  ditching,  bottoming,  borrowing,  road  crossings,  al 
terations  of  road  .crossings  and  water  channels,  and  the  con 
struction  of  temporary  roads,  provided  the  average  distance 
hauled  on  each  section,  be  the  same  as  stated  on  the  sched 
ule  here  annexed ;  but  if  the  actual  average  haul  on  any 
section  is  found,  on  completion,  to  have  been  greater  or  less 
than  the  distance  stated,  a  corresponding  addition  or  deduc 
tion  shall  be-  made,  of  one  cent  per  cubic  yard  per  hundred 
feet  which  the  actual  haul  exceeds  or  falls  short  of  that 
stated. 


60  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


EMBANKMENTS. 

The  embankments  to  be  formed  fifteen  feet  wide  on  the 
surface,  unless  otherwise  directed,  with  slopes  of  one  and 
one  half  horizontal  to  one  vertical.  Wherever  the  embank 
ment  is  formed  from  ditching  on  either  side,  such  ditching, 
and  the  crest  of  the  slopes  thereof  shall  in  no  case  approach 
within  six  feet,  nor  within  double  the  depth  of  ditch,  of 
the  foot  of  the  proper  embankment  slope,  allowing  always 
on  one  side  for  a  double  track ;  and  no  soft  mud  or  muck 
shall  be  allowed  to  enter  the  bank.  Wherever  watercourses 
or  new  channels  for  rivers  require  to  be  formed,  they  shall 
not  approach  within  once  and  one  half  of  the  depth  of 
such  stream,  plus  twenty-five  feet.  Care  shall  be  taken  in 
forming  embankments  to  exclude  all  perishable  material. 

SUBSIDENCE. 

To  allow  for  the  after  settlement  of  materials  on  em 
bankments,  they  shall,  when  delivered  to  and  accepted  by 
the  second  parties,  be  finished  to  the  full  width  to  the  fol 
lowing  heights  above  subgrades,  namely :  all  banks  below 
five  feet  in  height  to  be  finished  three  inches  above  sub- 
grade  ;  at  ten  feet  in  depth,  five  inches ;  at  twenty  feet,  six 
inches ;  and  twenty-eight  feet,  seven  inches ;  at  thirty-five 
feet,  eight  inches ;  and  at  forty  feet  in  depth,  nine  inches 
above  grade  ;  and  intermediate  heights  in  proportion  ;  the 
engineer  having  the  power  to  change  these  proportions  at 
his  discretion. 

EXTRA  EXCAVATION  AND  EMBANKMENT. 

Whenever  it  is  considered  necessary  to  increase  the  width 
of  the  road-way  for  turnouts,  water  stations,  or  depot 
grounds,  whether  in  excavation  or  embankment,  such  work 


SPECIFICATION.  61 

shall  be  done  at  the  contract  prices,  as  may  be  directed. 
The  opening  of  foundation  pits  in  simple  excavation,  where 
coffer-dams  or  such  like  expedients  are  necessary,  and  in 
places  where  such  expedients  are  necessary,  all  excavation 
above  the  water  line  shall  also  be  done  at  such  increase  or 
decrease  of  the  contract  price  as  shall  be  deemed  proper  by 
the  engineer. 

EMBANKING  AT  BRIDGES  AND  CULVERTS. 

The  contractor  for  earthwork  shall  not  carry  forward  in 
the  usual  way  any  embankments  within  fifty  feet  of  any 
piece  of  masonry,  finished  or  in  progress,  (counting  from 
the  bottom  of  the  slopes,)  but  shall  in  every  such  case  have 
the  earth  wheeled  to  the  walls  or  abutments,  and  carefully 
rammed  to  such  width  and  depth,  and  in  such  manner  as 
may  be  directed,  when  the  embankment  may  be  carried  on 
as  usual.  The  expense  attendant  upon  any  damage  or  re 
building  of  mason  work,  consequent  on  neglect  of  these 
directions,  shall  be  charged  to  the  account  of  the  first  party. 
In  case  the  mason  work  shall  not  be  finished  when  the  em 
bankment  approaches  it,  the  contractor  shall  erect  a  tempo 
rary  structure  to  carry  over  the  earth,  and  proceed  with  the 
embankment  on  the  opposite  side  ;  and  the  expense  of  said 
structure  shall  be  paid  by,  and  charged  to,  the  contractor  for 
masonry,  in  case  such  contractor  shall  have  delayed  beyond 
the  proper  or  required  time,  the  construction  of  the  mason 
work ;  but  if  the  mason  work  could  not  have  been  ready  in 
season  for  the  bank,  then  shall  the  expense  belong  to  the 
contractor  for  the  earthwork,  whose  price  for  graduation  is 
understood  to  comprehend  all  such  contingencies.  For  the 
above  work  of  wheeling  and  ramming  efficiently  the  earth 
around  any  piece  of  masonry,  the  contractor  shall  be  paid 

cents  per  cubic  yard,  by  the  engineer's  measurement. 

6 


62  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


ROADS     AND     WATERCOURSES. 

The  first  party  is  to  make  good  and  convenient  road 
crossings  wherever  directed,  and  shall  also  make  such  altera 
tions  of  existing  roads,  or  watercourses,  or  river  channels,  or 
such  new  pieces  of  these  pertinent  the  section  undertaken 
by  him,  as  may  be  required,  and  shall  be  paid  for  such 
work,  whether  earth,  rock,  or  masonry,  the  prices,  and  no 
more,  applicable  to  this  contract.  And  such  road  crossings 
or  other  alterations  referred  to,  he  shall  make  at  and  within 
such  times  and  in  such  form  and  manner  as  the  engineer 
shall  direct ;  and  whenever  the  operations  of  the  first  party 
interfere  with  a  travelled  road,  public  or  private,  either  by 
crossing  or  by  making  required  alterations  on  it,  the  first 
party  shall  so  operate  as  to  afford  at  all  times  a  safe  and 
free  passage  to  the  public  travel ;  and  the  first  party  shall 
be  liable  for  any  damage  to  which  the  second  parties  or  the 
railroad  company  may  become  lawfully  liable  by  reason  of 
his  neglect  to  maintain  a  safe  and  properly  protected  pas 
sage  for  the  current  travel. 

BALLASTING. 

Where  gravel  is  used  for  the  ballasting  of  the  road-bed, 
it  shall  be  of  a  quality  satisfactory  to  the  engineer,  and 
shall  be  spread  upon  the  road-bed  to  the  width  and  depth 
required.  When  broken  stone  is  used,  it  shall  be  of  dura 
ble  quality,  and  shall  be  broken  so  as  to  pass  through  a 
ring  of  three  inches  in  diameter.  The  quantity  will  be 
measured  in  the  road-bed  as  finished,  and  the  contractor 
will  be  required  to  keep  the  ditches  trimmed  and  clear. 


SPECIFICATION.  63 

RIP-RAP,     OR    RUBBLE     SLOPES. 

The  first  party  shall  distribute  rubble  stone  over  the 
slopes  of  earth  embankments,  whenever  required  to  do  so, 
to  protect  said  slopes  from  the  action  of  water.  Such  stone 
to  be  arranged  by  competent  hands,  and  laid  to  such  thick 
ness,  and  with  stones  of  such  size,  as  shall  be  directed. 
Where  the  contractor  has  rock  in  the  neighboring  cuttings 
which  is  available,  it  shall  be  reserved  and  applied  to  this 
purpose ;  and  when  not,  good  rock  shall  be  obtained  where 
the  contractor  can  conveniently  get  it. 

MEASUREMENTS. 

All  earth  or  rock  necessarily  moved  to  complete  the  grad 
ing  of  this  contract  according  to  direction,  will  be  measured 
in  excavation  only ;  and  if  the  contractor  (with  the  consent 
of  the  engineer,)  should  find  it  convenient  to  waste  earth 
from  an  excavation,  instead  of  carrying  it  to  its  proper  em 
bankment,  and  to  borrow  at  some  nearer  point  earth  for 
said  embankment  to  replace  that  which  was  wasted,  he 
shall  be  paid  for  the  earth  from  the  original  excavation  in 
the  order  of  its  most  economical  arrangement  for  the  sec 
ond  parties.  All  earth  moved  from  borrowing  pits  shall 
also  be  measured  in  excavation  only. 


78.    Specification  for   Masonry. 

FIRST     CLASS     MASONRY. 

First  class  masonry  will  apply  to  bridge  abutments  ex 
ceeding  twenty-five  feet  in  height,  to  the  ring  stones  of 
arches,  and  to  the  piers  of  bridges  in  running  water.  The 
stone  shall  be  laid  at  the  rate  of  one  header  to  two  stretches, 
disposed  so  as  to  make  efficient  bond.  No  header  to  be  less 


64  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

than  forty  incles  long,  and  no  stretcher  to  be  less  than 
eighteen  inches  in  width.  No  stone  less  than  twelve  inches 
in  thickness,  no  stone  to  have  a  greater  height  than  width, 
all  stones  to  be  placed  upon  the  natural  bed.  The  masonry 
throughout  to  have  hammer  dressed  beds  and  joints.  Verti 
cal  joints  to  be  continued  back  at  least  ten  inches  from  the 
face  of  the  wall.  The  mortar  joints  on  the  face  not  to  ex 
ceed  one  fourth  of  an  inch  in  thickness.  The  stone  to  be 
laid  with  regard  to  breaking  joints  in  the  adjoining  courses. 
The  stone  must  be  dressed  complete  before  laying,  and  not 
be  moved  after  being  placed  in  the  mortar.  The  face  will 
not  be  tooled,  but  only  roughly  hewed,  except  for  one  half 
inch  from  the  beds  and  joints,  where  it  will  be  hammered. 
The  ring  stones  of  arches  shall  have  beds  to  conform  to  the 
radius  of  the  arch,  with  the  end  joints  vertical,  and  be  made 
to  set  smoothly  on  the  centering,  with  the  beds  with  the 
proper  inclination.  Each  stone  must  extend  through  the 
whole  thickness  of  the  arch,  and  not  be  less  than  eight 
inches  thick  on  the  intrados.  No  spawls  or  pinners  will  be 
admitted.  The  ring  stone  shall  be  dimension  work,  ac 
cording  to  the  plans  furnished,  the  beds  and  joints  being 
truly  dressed,  but  the  faces  left  rough. 

All  first  class  work  shall  be  carefully  laid  in  good  cement 
mortar,  (see  Art.  Cement).  Each  stone  before  being  laid 
shall  be  carefully  cleaned  and  moistened;  and  masonry 
built  in  hot  weather  shall  be  protected  from  the  sun  as  fast 
as  laid,  by  covering  with  boards.  Copings  shall  be  built  of 
stone  of  equal  thickness,  neatly  dressed  and  laid. 

All  first  class  masonry  shall  be  well  pointed  with  cement 
pointing. 

SECOND     CLASS     MASONRY. 

To  be  applied  to  abutments  less  than  twenty-five  feet 
high,  ring  and  face  walls  of  bridges  and  culverts,  and  to 


SPECIFICATION.  65 

piers  not  in  running  water,  shall  consist  of  stones  cut  in 
bed  and  build  to  a  uniform  thickness  throughout,  before 
being  laid,  but  not  hammered ;  they  shall  be  laid  on  a  level 
bed,  and  have  vertical  joints  continued  back  at  right  angles 
at  least  eight  inches  from  the  face  of  the  wall.  The  work 
need  not  be  carried  up  in  regular  courses,  but  shall  be  well 
bonded,  having  one  header  for  every  three  stretchers,  and 
not  more  than  one  third  of  the  stones  shall  contain  less  than 
two  cubic  feet,  or  be  less  than  nine  inches  thick ;  and  none 
of  that  third  shall  contain  less  than  one  and  one  half  cubic 
feet,  or  be  less  than  six  inches  thick.  No  more  small  stones 
shall  be  used  than  necessary  to  make  even  beds,  the  whole 
to  be  laid  in  cement  mortar  and  pointed. 

THIRD     CLASS     MASONRY. 

Applicable  to  culverts,  and  to  the  spanded  backing  of 
arches,  shall  consist  of  strong  and  well  built  rubble  ma 
sonry,  laid  dry  for  culverts,  but  wet  for  backing.  The  cul 
verts  to  be  of  such  form  and  dimensions  as  the  engineer 
may  direct.  The  foundation  courses  of  the  side  walls  to 
consist  of  large  flat  stones,  from  eight  to  ten  inches  in  thick 
ness,  laid  so  as  to  give  a  solid  and  regular  basis  for  the  side 
walls.  The  side  walls  to  be  laid  with  sound  stone,  and  of 
sufficient  size,  and  with  beds  having  a  fair  bearing  surface 
and  good  bond.  The  covering  stone  for  culverts  being  not 
less  than  ten  inches  thick  for  two  feet  culverts,  twelve  inches 
for  three  feet  culverts,  and  fifteen  inches  for  four  feet  cul 
verts  ;  to  be  free  from  flaw  or  defect,  and  to  have  a  well 
bedded  rest  upon  each  side  wall,  of  not  less  than  twelve 
inches  for  two  and  three  feet  culverts ;  and  not  less  than  fif 
teen  inches  for  larger  ones.  In  case  such  stone  cannot  be 
obtained,  a  dry  rubble  arch  may  be  thrown  instead,  well 
pinned  and  backed ;  but  the  price  for  the  arch  shall  not  be 

6* 


66  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

more  than  the  general  price  for  third  class  masonry,  with  an 
allowance  for  the  centering. 


FOURTH    CLASS    MASONRY. 

Applicable  to  cattle-guards,  pavement  of  culverts,  and 
slope  and  protection  walls,  shall  consist  of  stones  of  not 
less  than  one  cubic  foot  in  contents,  so  laid  and  bonded 
as  to  give  the  greatest  degree  of  strength  in  preference 
to  appearance ;  being  laid  when  directed  with  beds  per 
pendicular  to  the  inclined  face.  Pavements  under  culverts 
shall  be  made  by  excavating  one  foot  in  depth  of  that 
part  to  be  paved,  which  space  shall  be  filled  with  flat 
stones  one  foot  wide,  set  on  edge,  close  together,  and 
made  to  present  an  even  upper  face. 


TIMBER    AND    PLANK    FOUNDATIONS. 

Timber  and  plank  foundations  require  the  beds  to  be  per 
fectly  well  levelled,  and  timber  of  such  dimensions,  and  so 
laid,  as  shown  by  the  plans  ;  to  be  well  bedded  and  brought 
to  an  even  and  level  top  surface.  The  spaces  between 
them  to  be  filled  and  well  rammed  with  such  material  as 
the  engineer  may  direct.  On  these  timbers  planks  shall  be 
laid,  and  trenailed  or  spiked  if  required.  The  materials 
shall  be  of  quality  and  shape  approved  by  the  engineer,  and 
the  price  shall  be  in  full  for  material  and  labor  in  laying  the 
whole  in  a  thorough  and  workmanlike  manner. 

PILING. 

Piling  may  be  used  either  as  bearing  piles  for  founda 
tions,  or  for  piled  bridges.  In  the  former  case  they  will  be 
bid  for  by  the  running  foot  driven,  and  in  the  latter  by  the 
stick  of  twenty-five  feet  in  length.  The  piles  in  either  case 


SPECIFICATION.  67 

must  be  straight  round  timber,  of  a  quality  approved  by 
the  engineer,  not  less  than  ten  inches  in  diameter  at  the 
small  end,  barked,  and  properly  banded  and  pointed  for 
driving.  They  shall  be  driven  in  such  places,  and  to  such 
depths  as  required,  and  the  heads  cut  off  square,  or  finished 
with  a  tenon  to  receive  caps,  as  may  be  required.  Bearing 
piles  will  be  cut  off  so  far  below  the  lowest  water  that  any 
timber  foundation  laid  thereon  shall  be  at  all  times  entirely 
immersed. 

CEMENT. 

Cement  when  used  shall  be  of  the  best  quality,  hydraulic, 
newly  manufactured,  well  housed  and  packed,  and  so  pre- 
.served  until  required  for  use.  And  none  shall  be  used  in 
the  work  until  tested  and  approved  by  the  engineer. 

CEMENT  MORTAR. 

The  proportion  of  sand  and  cement  for  construction  shall 
be  one  of  cement,  to  two  of  clean,  sharp  sand,  unless  in 
special  cases  the  engineer  direct  otherwise,  for  which  due 
allowance  shall  be  made.  It  shall  be  used  directly  after 
mixing,  and  none  remaining  on  hand  over  night  shall  be 
remixed. 

LIME    MORTAR. 

Lime  mortar  (which  in  all  cases  shall  contain  cement), 
will  consist,  unless  otherwise  directed,  of  two  parts  of  best 
quick  lime,  one  of  cement,  and  five  of  sand ;  the  ordinary 
mortar  of  lime  and  sand  being  first  properly  made,  and  the 
cement  thrown  in  and  thoroughly  mixed  immediately  be 
fore  using. 


68  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


CONCRETE. 

Whenever  concrete  is  required  to  be  used,  it  shall  be 
formed  of  clean  broken  stone,  cement,  and  sharp,  clean 
sand.  The  stone,  which  shall  be  of  satisfactory  quality, 
shall  be  broken  so  as  to  pass  through  a  ring  three  inches  in 
diameter.  The  cement  and  sand  shall  be  thoroughly  mixed 
in  the  proportions  already  described  for  cement  mortar. 
Thus  prepared,  it  shall  be  carefully  mixed  with  the  broken 
stone  in  the  proportion  of  one  of  mortar  to  two  or  two  and 
one  half  of  broken  stone,  as  the  engineer  upon  experiment 
shall  determine,  and  shall  be  immediately  laid  carefully  in 
its  place,  and  well  rammed.  The  concrete  shall  be  pro 
tected  on  the  sides  by  boards,  and  be  allowed  to  remain  un 
disturbed  after  laying  until  it  is  properly  set;  and  in  special 
cases  the  engineer  shall  direct  the  mode  of  application. 
For  the  proper  preparation  and  laying  of  such  concrete, 
there  shall  be  paid  the  price  applicable  to  second  class  ma 
sonry.  The  contractor  shall  furnish  all  tools  and  plank 
necessary  to  the  operation. 

POINTING. 

All  masonry  in  cement  or  lime  will  be  finished  with  a 
good  pointing  of  cement,  without  extra  charge. 

/ 

BRICKWORK. 

When  bricks  are  required,  or  allowed  to  be  used,  they 
shall  consist  of  sound,  hard-burned  brick,  laid  in  cement,  or 
common  mortar,  as  directed,  and  no  soft  or  salmon  brick 
will  be  admitted ;  and  none  but  regular  bricklayers  must  be 
employed. 


SPECIFICATION.  69 


CENTERING   AND    BACKING. 

The  whole  top  of  all  arches,  whether  brick  or  stone,  shall 
be  finished  by  plastering  with  a  good  coat  of  cement,  so  as 
to  prevent  the  percolation  of  water,  and  turn  it  away  from 
the  arch.  The  centering  shall  be  such  as  the  engineer  ap 
proves  of  in  every  respect,  and  shall  not  be  removed  until  he 
directs.  The  cost  of  backing  to  be  included  in  the  price 
bid.  For  arches  of  more  than  twenty-five  feet  span,  com 
pensation  shall  be  made,  at  the  engineer's  estimate,  for  the 
extra  value  and  cost  of  the  centering  proper  for  large  arches. 

GENERAL    PROVISION. 

79.  The  engineer  reserves  the  right  to  require  the  whole 
or  any  part  of  the  above  described  work  of  masonry  to  be 
laid  in  cement,  lime,  mortar,  or  dry,  at  his  discretion.     First 
and  second  class  masonry,  and  brickwork,  will  be  bid  for 
at  prices  for  laying  in  cement,  from  which  will  be  deducted 
fifty  cents  per  yard  if  laid  in  lime  mortar,  and  one  dollar  if 
laid  dry.     Third  and  fourth  class  masonry  at  prices  for  lay 
ing  dry,  to  which  wiU   be  added  fifty  cents  per  yard  if  laid 
in  lime  mortar,  and  one  dollar  if  laid  in  cement. 

SCAFFOLDING. 

80.  Nothing  shall  be  allowed  for  workmanship  or  timber 
of  any  scaffolding  used  in  the  construction  of  timber  bridges, 
or  in  carrying  up   abutments,  piers,  coffer-dams,  or  other 
wise.     Should  the  timber  used  in  any  coffer-dam  be  carried 
away  by  floods,  the  renewal  of  it  shall  fall  upon  the  first 
party. 


70  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FOUNDATIONS. 

81.  The  foundations  for  all  structures  shall  be  executed 
by  the  contractor  for  masonry  in  such  manner  and  to  such 
depth  as  to  secure  a  safe  and  secure  foundation,  of  which 
the  engineer  will  judge.  If  a  natural  foundation  cannot  be 
procured  at  a  reasonable  depth,  then  the  contractor  shall 
prepare  such  artificial  foundation  as  the  engineer  may  di 
rect.  The  stuff  moved  from  the  foundations,  if  of  tht: 
proper  quality,  shall  be  deposited  in  the  adjoining  embank 
ment,  provided  the  site  for  said  embankment  has  been 
cleared  of  all  perishable  material.  So  much  of  the  stuff  as 
shall  not  be  fit  for  the  embankment,  and  all  roots,  stumps, 
etc.,  shall  be  deposited  beyond  the  limits  of  the  clearing,  so 
as  not  to  obstruct  roads,  watercourses,  or  ditches. 

For  the  earth  moved  from  such  foundations,  and  for  all 
earth  used  according  to  direction,  in  the  construction  of  cof 
fer-dams,  there  shall  be  paid cents  per  cubic  yard. 

Whenever  it  may  be  necessary  to  pump  or  bale  water  in 
the  foundations,  the  contractor  shall  furnish  the  pumps  or 
buckets,  and  all  scaffolding  and  apparatus  necessary  to 
work  them.  He  shall  be  allowed  the  net  cost  of  all  labor 
employed  in  the  operations  of  pumping  or  baling  water, 
and  shall  make  a  monthly  return  to  the  engineer  of  the 
value  of  such  labor,  provided  that  these  operations  are  con 
ducted  in  an  economical  manner,  with  efficient  men,  pumps, 
and  tools,  under  the  direction  and  to  the  satisfaction  of  the 
engineer.  He  shall  also  be  allowed  such  compensation  for 
the  use  of  the  pumps  and  apparatus,  and  for  superintend 
ence,  as  the  engineer  shall  judge  to  be  fair  and  reasonable. 


SPECIFICATION.  71 


TRESTLE    WORK. 

82.  Includes   all  wooden  structures  commonly  used  as 
substitutes  for  abutments  and  piers,  and  for  farm  passes, 
etc.,  etc.     These  shall  be  built  according  to  the  plans  fur 
nished,  and  directions  given  by  the  engineer,  of  sound,  du 
rable  material,  to  be  approved  by  him.     The  price  bid  shall 
be  by  the  thousand  feet  board  measure,  and  will  be  consid 
ered  as  in  full  for  all  material  except  iron,  and  for  the  labor 
of  building  and  erecting  complete.     The  iron  used  will  be 
of  the  best  American,  and  the  workmanship  of  approved 
quality.     The  bids  will  be  by  the  pound,  and  will  cover  all 
cost  of  material  and  the  labor  incident  to  its  use.     Spikes 
and  nails  when  used  will  be  furnished  by  the  contractor  at 
cost. 

BRIDGING. 

83.  Contractors  may  submit  plans  for  bridging  in  con 
nection  with,  or  separate  from  their  bids ;  but  the  engineer 
of  the  company  may  reject  such  plans  if  he  choose,  and 
substitute  others,  which  if  the  contractor  decline  building  at 
the  approved  prices,  may  be  left  to  other  parties.     In  every 
case,  the  exact  manner  of  building,  erecting,  adjusting,  and 
finishing  bridges,  and  the  determination   of  the  nature  and 
amount  of  material,  will  be  specified  by  the  engineer.     The 
price  bid  must  be  by  the  running  foot  of  the  whole  length 
of  bridge,  as  erected  and  finished  complete. 


72  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


84.    Specifications  for    Superstructure. 

SUBSILLS. 

To  maintain  the  track  in  good  adjustment  until  em 
bankments  are  settled,  subsills  will  be  laid  on  certain 
banks,  and  likewise  in  cuts  where  the  imperfect  nature  of 
the  bottoming  may,  in  the  opinion  of  the  engineer,  render 
them  expedient.  These  subsills  to  be  fairly  bedded  in  the 
earth  or  ballasting,  and  carefully  adjusted  and  rammed  so 
as  to  correspond  with  the  grade  lines  given  by  the  engineer. 
An  additional  piece  of  sill,  four  feet  long,  shall  be  laid  at 
each  joint  of  the  subsill,  either  under  the  sill,  or  alongside, 
as  may  be  directed.  The  sills  will  be  of  3  X  9  plank,  in 
length  of  twelve,  fifteen,  eighteen,  and  twenty-one  feet ;  of 
which  one  fourth  may  be  below  fifteen,  one  fourth  below 
eighteen,  and  one  fourth  below  twenty-one  feet.  The  plank 
must  be  square  at  the  ends,  and  of  sound,  durable  material, 
and  not  have  more  than  two  inches  waine  on  one  end  only. 
There  will  be  about  25,000  feet,  board  measure,  laid  per 
mile  where  it  may  be  required,  and  660  joint  sills,  3X9 
inches,  and  four  feet  long.  When  the  depth  of  stuff  to  be 
moved  to  admit  the  subsills  exceeds  six  inches,  an  allow 
ance  shall  be  made  for  extra  labor,  the  amount  of  which 
shall  be  noted  by  the  assistants  on  their  receiving  notice  of 
such  extra  labor  from  the  contractor  or  his  agent. 

CROSS    TIES. 

The  cross  ties  shall  be  of  white,  black,  or  yellow  oak, 
burr  oak,  chestnut,  red  elm,  black  walnut,  or  other  sound 
timber  of  suitable  character  in  the  opinion  of  the  engineer. 
Eight  feet  long,  and  not  more  than  three  inches  out  of 


SPECIFICATION.  73 

straight,  hewn  to  a  smooth  surface  on  two  parallel  plane 
faces  six  inches  apart,  the  faces  being  not  less  than  seven 
inches  wide  for  at  least  half  of  the  number,  and  the  remain 
der  not  less  than  six  inches  wide.  The  ties  shall  be  carefully 
and  solidly  laid  on  the  subsills,  or  ballasting,  or  earth  previ 
ously  properly  prepared,  so  as  to  give  the  true  planes  re 
quired  by  the  rails,  whether  on  straight  or  curved  lines. 
They  shall  be  laid  at  the  rate  of  eight  ties  to  each  eighteen 
feet  rail.  All  imperfect  ties  shall  be  excluded  by  the  track- 
laying  party.  The  surface  of  the  ties  to  be  faithfully  ad 
justed  to  the  grades  given,  and  to  the  web  of  the  rail ;  and 
the  rail  to  be  truly  laid  and  firmly  spiked  so  as  to  corre 
spond  neatly  to  the  alignment  of  the  road.  There  will  be 
about  2,500  ties  required  per  mile  of  road. 

CHAIRS   AND   JOINTS. 

When  chairs  are  used,  they  shall  be  such  as  directed  by 
the  engineer,  and  furnished  by  the  company,  and  shall  be 
well  and  accurately  placed  and  spiked  in  such  manner  and 
position  as  required.  When  chains  are  used,  the  largest 
ties  shall  be  selected  for  the  joints.  When  the  joint  is 
made  by  fishing,  there  will  be  no  tie  directly  under  the 
joint. 

RAILS. 

The  rails  will  weigh  about  sixty  pounds  per  lineal  yard. 
No  rail  shall  be  laid  on  the  tangents  which  is  in  any  way 
twisted  or  bent.  It  shall  be  the  duty  of  the  first  party  to 
correct  and  make  true  any  crooked  rails  received  by  him, 
also  to  bend  to  the  proper  curve,  and  in  such  a  manner  as 
not  to  affect  the  strength  of  the  bar,  all  rails  laid  in  curves. 
Punching  of  rails,  and  cutting,  will  also  be  done  by  the 
contractor. 

7 


74  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


TRACK   LAYING. 

The  materials  composing  the  track  will  be  furnished  by 
the  company,  and  it  will  be  laid  in  the  best  manner  accord 
ing  to  the  conditions  following.  The  track  will  be  laid 
across  ties,  and  the  ties  at  the  proper  places  on  subsills. 
Where  the  sills  are  used,  they  will  be  laid  with  four  feet 
blocks  at  the  joints,  and  with  six  feet  blocks  at  the  rail 
joints,  the  whole  being  set  to  their  places  by  stakes,  and  by 
the  engineer's  directions,  and  mauled  down  to  a  perfect 
bearing,  being  settled  at  least  half  an  inch  by  mauling. 
The  cross  ties  will  be  placed  uniformly  distant,  (twenty- 
eight  inches  from  centre  to  centre).  The  iron  must  be  so 
cut  or  selected  that  the  joints  of  the  parallel  rails  shall  be 
within  two  inches  of  being  opposite  to  each  other ;  no  joint 
tie  being  allowed  a  greater  amount  of  askew  than  this, 
whether  on  tangents  or  curves.  A  slip  of  metal  shall  be 
inserted  at  the  rail  joints  while  laying,  to  keep  the  rails 
apart  sufficiently  to  allow  for  expansion,  which  thickness, 
(depending  upon  the  temperature,)  shall  be  fixed  by  the  en 
gineer.  Notches  to  be  cut  at  the  centre  of  each  bar,  to  cor 
respond  with  half  a  spike,  to  prevent  longitudinal  motion  of 
the  rails.  Each  joint  chair  to  be  fastened  with  four  spikes. 
Two  spikes  at  each  end  of  each  tie  upon  straight  lines  and 
upon  curves  of  less  than  1,500  feet  radius  at  the  outer  end 
of  the  tie  two  spikes  outside  and  one  inside,  and  at  the  in 
ner  end  two  spikes  outside  and  one  inside  of  the  rail.  Upon 
curves  the  outer  rail  to  be  raised  by  such  an  amount,  de 
pending  on  the  radius  of  curvature,  as  the  engineer  may 
direct 


SPECIFICATION.  75 


TURNOUTS. 

The  contractor  to  put  in  such  turnouts  and  sidings,  with 
the  necessary  frogs  and  switches,  as  may  be  required ;  the 
frogs  and  switches  to  be  firmly  and  truly  placed  in  position 
so  as  to  work  easily. 

i  FILLING   AND    DITCHING. 

The  stuff  moved  in  bedding  the  sills  and  ties,  to  be 
placed  between  the  latter.  The  ditches  to  be  properly 
cleaned  out  after  the  track  is  laid ;  the  filling  never  to  rise 
higher  than  the  top  of  the  cross  tie.  Any  surplus  stuff  to 
be  moved  out  of  the  cuts,  or  if  on  embankment,  to  be 
thrown  over  the  bank,  leaving  the  track  and  road-bed  in  a 
neat  and  workmanlike  shape. 

DELIVERY    OF   MATERIALS. 

The  ties  and  sills  to  be  delivered  at  some  point  on  the 
road  as  near  as  possible  to  the  places  where  they  are  to  be 
used,  in  no  case  requiring  more  than  one  thousand  feet  of 
land ;  to  be  so  piled  as  easily  to  be  counted  and  inspected. 
The  bids  for  ties  will  be  by  the  piece  ;  the  proposal  stating 
the  number  and  conditions ;  the  sills  to  be  bid  for  by  the 
thousand,  board  measure.  All  material  furnished  in  con 
nection  with  track  laying  to  be  delivered  in  such  manner 
and  time  as  to  comply  in  good  season  with  the  contract  for 
laying  the  rails. 

MEASUREMENT    OF   TRACK. 

The  measurement  of  track  laid  shall  include  the  turnouts, 
measuring  from  heel  to  heel  of  switch.  No  extra  allow 
ance  being  made  for  putting  in  frogs  or  switch  machinery. 


76  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


85.    Specification  for  Fencing. 

Bids  for  fencing  will  be  by  the  running  foot,  or  mile,  in 
cluding  both  sides  of  the  road.  Where  required,  it  will 
consist  of  posts  placed  eight  feet  apart  from  centre  to  cen 
tre,  set  three  feet  into  the  ground,  either  by  digging  or  bor 
ing,  and  not  by  mauling.  The  posts  shall  be  of  oak,  elm, 
chestnut,  or  other  durable  wood,  not  less  than  eight  inches 
in  diameter  at  the  top,  barked  and  charred  when  put  into 
the  ground.  The  boards  to  be  6  X  1  inches,  and  to  square 
sixteen  feet  long,  to  be  placed  six  inches  apart  vertically, 
and  fastened  to  the  posts  with  twopenny  nails  at  each  bear 
ing,  and  breaking  joint  with  each  other.  There  will  be  five 
bars  in  depth,  the  top  of  the  uppermost  being  five  feet  from 
the  ground.  In  side  hill  and  in  ground  liable  to  slide,  par 
ticular  care  shall  be  taken  to  place  the  posts  firmly  in  the 
ground.  At  cattle  guards,  the  fence  will  be  turned  in  to 
the  proper  distance,  and  such  arrangement  made  as  to  pre 
vent  the  passage  of  animals. 


86.    General  Provisions. 

CLASSIFICATION. 

The  classification  of  material  excavated  will  be  referred 
to  the  engineer,  in  all  cases  where  the  nature  of  the  mate 
rial  is  questioned,  and  his  judgment  taken  thereon.  Also 
all  material  used  in  structures  will  be  submitted  to  the  in 
spection  of  the  engineer  or  his  assistants. 


SPECIFICATION.  77 


QUANTITIES    AND    QUALITIES    APPROXIMATE. 

The  quantities  and  qualities  of  work  presented  in  the 
schedule  are  merely  approximate,  and  the  information  given 
on  the  maps  and  profiles  in  relation  thereto  is  according  to 
the  best  present  knowledge.  The  company  retains  the  right 
to  change  at  any  time  during  the  progress  of  the  work,  the 
alignment,  grades,  and  width  of  the  road,  or  any  part 
thereof;  and  also  the  limits  of  the  sections,  or  to  alter  the 
character,  vary  the  dimensions,  or  change  the  location  of 
structures,  or  substitute  one  kind  of  work  or  material  for 
another,  or  to  omit  entirely,  when  found  necessary,  or  to  re 
quire  to  be  built  where  not  now  contemplated;  and  the 
contractor  shall  carry  into  effect  all  such  alterations  when 
required,  without  the  contract  prices  being  thereby  affected, 
unless  the  aggregate  value  of  all  work  contemplated  by  the 
contract  be  changed  full  twenty  per  cent.,  in  which  case  a 
fair  allowance,  either  for  the  company  or  the  contractor, 
shall  be  made  by  the  engineer.  In  case,  however,  the  ag 
gregate  value  of  the  work  be  changed  by  over  twenty  per 
cent,  of  the  original  amount,  and  the  contractor  be  not  sat 
isfied  with  the  altered  compensation,  then  said  contractor 
may  throw  up  said  contract,  on  condition,  that  within  ten 
days  after  receiving  notice  from  the  engineer  of  such  altera 
tion,  he  give  written  notice  to  the  engineer  or  the  company 
of  his  desire  to  do  so.  In  which  case,  as  in  other  cases  of 
throwing  up  the  contract,  he  shall  as  soon  as  desired,  give 
peaceable  possession  to  the  company  or  their  agents  ;  leav 
ing  also  in  their  possession  any  tools  or  machinery  upon 
which  they  have  advanced  any  thing ;  and  the  company 
may  then  settle  with  the  contractor  on  the  measure  of  dam 
ages  which  either  shall  suffer. 

7* 


78  HANDBOOK   OF  RAILROAD  CONSTRUCTION. 


BASE    FOR    ESTIMATING    EFFECT    OF    CHANGES. 

The  base  for  estimating  any  changes  as  above  mentioned 
is  understood  to  be  the  schedule  exhibited  at  the  letting. 

NO    LIQUOR,    AND    GOOD    ORDER. 

The  contractor  shall  not  sell,  or  allow  to  be  sold  or 
brought  within  the  limits  of  his  work  any  spirituous  liquors, 
and  will  in  every  way  discountenance  their  use  by  persons 
in  his  employ.  He  will  do  all  in  his  power  by  his  own  act, 
or  by  assisting  the  officers  of  the  county,  or  of  the  corpora 
tion,  in  maintaining  the  laws  and  such  regulations  as  con 
duce  to  good  order  and  peaceable  progress,  and  prevent  en 
croachment  on  the  rights  of  persons  or  property ;  and  he 
shall  discharge  from  his  service,  when  required  by  the  en 
gineer,  any  disorderly,  dangerous,  insubordinate,  or  incom 
petent  person,  and  refuse  to  receive  into  his  employ  any 
who  may  have  been  discharged  for  such  cause  from  other 
parts  of  the  work. 

MONTHLY   ESTIMATES. 

Measurements  and  estimates  shall  be  made  by  the  en 
gineer  once  in  each  month,  by  means  of  which  may  be 
known  approximately  the  amount  of  work  done,  and  the 
contractor  shall  be  entitled  to  payment  therefor  at  such  rates 
below  his  contract  prices  as  the  engineer  or  president  of  the 
company  deems  expedient ;  it  being  understood  that  the 
contractor  has  no  claim  on  account  of  any  material  not  laid 
in  its  place  in  the  roadway,  or  for  labor  bestowed  thereon ; 
and  the  quantities  shall  be  estimated  from  the  dimensions 
when  so  laid,  though  on  the  advice  of  the  engineer,  advan 
ces  may  be  made  on  such  material  when  delivered  for  use,  in 


SPECIFICATION.  79 

which  case  it  becomes  the  property  of  the  company,  in  the 
contractor's  care  and  keeping,  and  he  becomes  liable  for  its 
loss  or  injury. 

EXTRA    WORK. 

No  claim  for  extra  work  or  for  work  not  provided  for  in 
the  contract  shall  be  allowed,  unless  a  written  order  to  per 
form  such  work  shall  have  been  given  by  the  engineer ;  or 
that  the  work  be  subsequently  certified  by  him,  and  the  cer 
tificate  produced  at  the  time  of  demanding  the  payment  of 
the  monthly  estimate  next  after  such  work  shall  have  been 
performed. 

SUB-CONTRACTS. 

The  contractor  will  be  required  to  perform  the  work  him 
self,  and  no  sub-contracts  relieving  him  from  the  responsi 
bility  of  a  proper  performance  of  his  contract  will  be  per 
mitted,  unless  by  the  written  consent  of  the  president  of 
the  company.  And  no  moneys  shall  be  paid  to  any  such 
sub-contractor  for  work  or  materials,  without  sufficient  au 
thority  from  the  principal  contractor. 

WHEN    WORK   TO    BE    COMMENCED. 

On  the  acceptance  of-a  proposal,  the  chief  engineer  will 
give  notice  thereof  to  the  person  proposing,  by  letter  di 
rected  to  his  stated  address ;  and  in  twenty  days  from  the 
date  of  such  notice,  provided  there  be  no  impediment  on 
the  part  of  the  company,  or  in  twenty  days  after  such  im 
pediment  is  removed  if  there  be,  the  work  shall  be  begun 
with  an  adequate  force,  and  from  that  time  be  prosecuted 
vigorously  until  its  completion. 


80  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


HOW   TO    PROGRESS. 

It  shall  be  understood  that  proper  progress  is  not  made, 
if  the  amount  of  work  done  in  each  month  is  not  in  due 
proportion  to  the  total  amount  to  be  done  up  to  the  time 
fixed  for  completion  by  the  contract;  in  which  case  the 
engineer  shall  call  the  attention  of  the  contractor  (or  who 
ever  may  be  in  charge  of  the  work  if  the  contractor  be 
absent,)  to  the  fact,  and  state  to  him  what  additional 
exertion  is  necessary  to  be  made,  and  what  further  force  is 
required,  in  such  reasonable  time  as  may  be  prescribed. 

PUTTING     ON    MORE    FORCE. 

In  default  of  the  contractor's  making  such  additional  ex 
ertion,  and  supplying  such  force,  the  chief  engineer,  or  pres 
ident  of  the  company  may  have  such  force  sent  to  the  work, 
and  the  necessary  buildings  may  be  erected  to  receive  them 
at  the  contractor's  charge  and  expense,  who  shall  receive  the 
said  force  in  his  employ,  and  work  it  at  whatever  price  it 
may  have  been  found  necessary  to  employ  it,  without  di 
minishing  the  previous  force  of  the  work,  and  regarding 
always  such  extra  force  as  if  employed  by  himself. 

CAUSES    FOR    DETENTION. 

There  shall  be  no  claim  for  detention  on  account  of  work 
not  being  laid  out,  unless  a  written  notice  three  days  in  ad 
vance,  that  it  is  required,  shall  have  been  given  to  the  en 
gineer;  and  the  damage  for  such  detention  shall  be  esti 
mated  by  the  engineer.  The  right  of  way  shall  be  fur 
nished  by  the  company,  but  if  it  fail  to  do  so  for  any 
particular  place,  damages  for  detention  shall  not  be  claimed 
unless  the  contractor  be  detained  full  twenty  days  after  he 


SPECIFICATION.  81 

shall  have  given  written  notice  to  the  engineer  of  his  wish 
to  commence  work  at  such  place.  Then  the  engineer  may 
either  estimate  to  him  the  amount  of  damage  which  he  shall 
take  as  satisfactory,  or  he  may  extend  the  time  of  the  com 
pletion  of  such  work  by  as  many  days  beyond  the  contract 
time,  as  the  contractor  is  detained  beyond  the  twenty  days 
following  his  notice  to  the  engineer. 

THE     ENGINEER. 

In  all  cases  where  the  word  "  engineer  "  is  used,  the  en 
gineer  in  charge  of  construction  is  meant ;  but  the  direc 
tions  of  any  subordinate  engineer  shall  be  obeyed  when 
given  in  regard  to  any  of  the  ordinary  operations,  or  where 
they  are  evidently  in  accordance  with  the  specifications,  or 
when  transmitting  the  orders  of  his  superiors.  In  other 
cases  they  may  be  referred  to  the  resident  engineer,  and 
finally  to  the  chief  engineer,  he  being  the  authorized  officer, 
at  the  time  acting  in  that  capacity. 

CONTRACTOR. 

The  word  "  contractor "  applies  to  and  includes  all  per 
sons  contracting  jointly,  any  one  of  whom  shall  be  con 
sidered  the  authorized  agent  for  and  in  behalf  of  his  asso 
ciates,  and  empowered  to  receipt  payment  of  moneys, 
receive  and  act  upon  orders. 

THE     CONTRACT. 

87.  This  is  the  mutually  binding  legal  article  of  agree 
ment  between  the  contractor  and  the  company,  specifying 
the  times  of  completing,  manner  of  payment,  and  describ 
ing  the  work  which  is  to  be  done.  Thus :  — 


82  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 


A  AND   B  RAILROAD   COMPANY. 

Contract. 

Graduation  on  sections  A  C  D, 
Masonry  on  sections  A  C  D, 
Ballasting  on  sections  A  C  D, 
Bridging  on  sections  A  X  T, 
Fencing  on  sections  O  O  O, 
Sills  and  ties  on  sections  O  O  O, 
Track  laying  on  sections  O  O  O. 


Contractors. 


Articles  of  agreement  made  and  concluded  this  first  day 

of  January,  A.  D.  1857,  between of  the  first  part, 

and  the  A  and  B   Railroad  Company  of  the  second  part, 

being  a  company  duly  incorporated  by  the  State  of 

of  the  second  part,  whereby  it  is  mutually  agreed  as  fol 
lows,  namely :  The  said  ppa^s  of  the  first  part  hereby  agree 
to  and  with  the  said  party  of  the  second  part  that  t^y  will 
perform  in  a  substantial  and  workmanlike  manner  the  fol 
lowing  work,  namely :  — 

\_The  work  here  described.'] 

The  said  work  to  be  performed  and  completed  agreeably 
to  the  directions  and  to  the  approval  of  the  chief  engineer 
of  said  company  for  the  time  being,  and  subject  to  all  the 
general  provisions  of  the  specification  attached  to  and  form 
ing  a  part  of  this  agreement,  and  also  subject  to  such  of 
the  special  provisions  of  said  specifications  as  are  applica 
ble  to  the  work  hereby  contracted  for. 

And  in  consideration  of  the  full  and  faithful  performance 
by  the  said  ppaar^s  of  the  first  part  of  this  agreement  on 


SPECIFICATION.  83 

part,  the  said  party  of  the  second  part  hereby  agrees  to  pay 
for  the  same  in  the  time  and  in  the  manner  hereinafter  men 
tioned,  at  the  rates  as  follows,  namely :  — 

[Here  insert  the  items  and  corresponding  prices.~] 

It  is  mutually  agreed  that  this  contract  applies  only  to 
those  items  to  which  prices  are  attached,  and  that  where  it 
embraces  both  labor  and  materials  introduced  in  the  work, 
such  prices  are  in  full  compensation  therefor  when  intro 
duced  in  the  manner  required.  When  it  embraces  materi 
als  only,  such  prices  are  in  full  compensation  for  the  mate 
rials  and  the  labor  necessary  to  deliver  the  same  to  the 
company,  and  when  it  embraces  labor  only,  such  prices  are 
in  full  compensation  for  such  labor,  and  every  incident 
to  its  complete  and  proper  performance.  In  every  case  the 
estimate  for  ascertaining  the  amount  of  compensation  shall 
be  made  by  the  engineer  from  the  actual  work,  from  the 
material  furnished,  or  from  that  on  which  the  labor  con 
tracted  for  is  bestowed. 

It  is  also  agreed  that  partial  payments  shall  be  made 
from  time  to  time  during  the  progress  of  the  work  as  fol 
lows  :  — 

[Times  and  manner  of  payment."] 

And  that  in  thirty  days  after  the  contract  is  fully  completed 
to  the  satisfaction  of  the  chief  engineer  of  the  company  for 
the  time  being,  and  the  work  is  surrendered  to  and  accepted 
by  the  company,  a  final  measurement  and  estimate  thereof 
shall  be  made  under  the  direction  of  the  chief  engineer,  and 
be  duly  certified  by  him,  on  the  return  of  which  to  the  pres 
ident  of  the  company  the  whole  amount  then  found  to  be 
due  to  the  said  ppaarrt^s  of  the  first  part  shall  be  paid  to  £™ 
on  demand  as  follows :  — 

[Insert  mode  of  payment.'] 
And  it  is  also  hereby  further  agreed,  that  bank-bills  current 


84  HANDBOOK  OP  RAILROAD   CONSTRUCTION. 

in  the  State  of shall  be  accepted  for  cash  in  pay 
ment  for  all  claims  under  this  contract. 

And  the  said  pP^  of  the  first  part  further  aagfeeees  that  in 
twenty  days  after  t£®  shall  be  notified  to  do  so,  as  provided 
for  in  said  specifications,  tj®  will  begin  the  work  hereby 
contracted  to  be  performed,  with  a  force  of  all  kinds  suffi 
cient  for  its  completion  in  the  time  herein  prescribed,  and 
that  fa*  will  finish  and  deliver  the  same  to  the  company 
fully  completed  in  all  its  parts  as  follows :  — 


And  the  said  specifications  hereunto  annexed  are  hereby 
made  a  component  part  of  this  contract  and  (except  so  far 
as  any  provision  therein  may  not  be  pertinent  to  the  sub 
ject-matter  of  the  contract  as  may  be  specially  modified 
herein,)  shall  be  looked  to  in  ascertaining  the  meaning,  ex 
tent,  and  purport  of  this  agreement,  and  in  determining  the 
rights,  powers,  duties,  privileges,  and  obligations  of  the  con 
tracting  parties  as  to  any  particular  embraced  therein. 

In  virtue  whereof  the  said  ppaart^s  of  the  first  part  hhaavse  here 
unto  set  tj2r  hand  and  seal,  and  the  said  party  of  the  second 
part  have  caused  their  president  to  subscribe  his  name  and 
affix  the  corporate  seal  of  the  company  hereto,  all  done  in 
triplicate  the  day  and  year  first  above  written. 

Contractor's  name,  [SEAL.] 

President's  name,  [SEAL.] 

SOLICIT   FOR   BIDS. 

88.  The  approximate  estimates,  plans,  and  profiles  being 
made,  and  other  preliminaries  settled,  proposals  for  execut 
ing  work  are  solicited  by  the  public  papers.  Thus  :  — 


SPECIFICATION.  85 

NEW  YORK,  January  1,  1857.  > 

Office  of  the  A  and  B  Railroad  Company.  J 

Proposals  for  executing  the  graduation,  bridging,  ma 
sonry,  and  track  laying,  and  for  the  supply  of  materials 
upon  the  A  and  B  railroad  will  be  received  at  this  office 
until  the  31st  day  of  January,  1857. 

Plans,  profiles,  and  schedules  of  amounts  of  work  may 
be  seen,  and  blank  bids  obtained  by  application  at  this 
office. 

All  proposals  must  be  directed  to  the  chief  engineer  of 
the  A  and  B  Railroad  Company. 

No  bids  will  be  received  after  January  31st,  at  12,  M. 
Per  order, 

C.  D.,  Secretary  A  and  B  R.  R.  Co. 

FORM    FOR    A    BID. 

89.  That  proposers  may  make  their  bids  in  a  convenient 
form  for  comparison,  a  blank,  somewhat  like  the  following, 
is  given  them  to  fill  out. 


8 


86 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Number  of  Section. 

Sec.  1. 

Sec.  2. 

Sec.  3. 

Sec.  4. 

Length  in  miles. 

It 

l| 

12 

1* 

Graduation. 

Clearing  and  grubbing, 

Price  per  acre, 

Cost  on  the  section, 

Earth  excavation, 

Price  per  yard, 

Cost  on  the  section, 

Loose  rock  excavation, 

Price  per  yard, 

Cost  on  the  section, 

Solid  rock  excavation, 

Price  per  yard, 

Cost  on  the  section, 

Average  haul  on  section, 
Ballasting, 
Price  per  yard, 

Cost  on  the  section, 

Whole  cost  of  graduation, 

Masonry. 

First  class  masonry, 

Price  per  yard, 

Cost  on  the  section, 

Second  class  masonry, 

Price  per  yard, 

Cost  on  the  section, 

Third  class  masonry, 

Price  per  yard, 

Cost  on  the  section, 

Foundation  timber, 

Cost  per  M.,  b'd  measure, 

Cost  on  the  section, 

Excavation  for  foundation, 

Price  per  yard, 

Cost  on  section, 

Rip  rap, 
Price  per  yard, 

Cost  on  the  section, 

Whole  cost  of  masonry, 

Bridging. 

Detailed  as  above, 

Track  laying. 

Fencing. 

SPECIFICATION. 


87 


This  form  being  filled  out,  evidently  gives  the  cost  of 
each  or  all  of  the  items  upon  any  one  or  all  of  the  sections, 
the  cost  of  all  the  items  upon  any  one  section  being  at  the 
foot  of  that  section,  and  the  whole  cost  of  any  one  item  at 
the  extreme  right  and  on  the  line  of  that  item. 

On  the  bottom  of  the  form  is  printed,  "  The  undersigned 
having  read  the  specifications,  and  made  due  examination, 
hereby  proposes  to  the  A  and  B  Railroad  Company,  to  per 
form  the  work  in  the  above  schedule,  to  which  £*  Jave  set 
figures,  at  those  prices  and  under  the  conditions  described, 
and  upon  acceptance  of  this  proposal  by  the  company, 
Mm?  the'msdves  to  enter  into  a  written  contract  to  that  effect, 
and  to  furnish  the  required  security. 

Name, 

Address, 

Name  of  Surety, 

Address  of  Surety." 


COMPARISON    OF    BIDS. 

90.    The  bids  being  received,  are  compared  as  follows : 


Graduation. 

Masonry. 

Name  of 

bidder. 

1 

Sec.l. 

Sec.  2. 

Sec.  3. 

Sec.  4. 

Total. 

Sec.  1. 

Sec.  2. 

Sec.  3.  'Sec.  4. 

Total. 

I 

A 

B 

C 

88 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Bridging. 

Superstructure. 

Name  of 

bidder. 

i 

Sec.  1. 

Sec.  2. 

Sec.  3. 

Sec.  4. 

Total. 

Sec.  1. 

Sec.  2. 

Sec.  3. 

Sec.  4. 

Total. 

A 

B 

C 

Fencing. 

Name  of 

Grand 

bidder. 

Total. 

Sec.  1. 

Sec.  2.:Sfic.  3.  Sec.  4. 

Total. 

A 

B 

C 

From  which  the  names  may  be  easily  selected  either  for 
one  or  more  sections,  for  any  or  all  of  the  items,  that  shall 
give  the  least  cost. 


CHAPTER   V. 

LAYING  OUT   WORK. 


91.  THE  running  of  the  line  consists  in  placing  a  stake 
at  every  one  hundred  feet  upon  tangents,  and  at  every  fifty 
feet  distance  upon  sharp  curves ;  also  a  permanent  post  at 
each  tangent  point,  and  at  points  of  compound  and  reversed 
curvature.     This  is  the  centre  line,  the  axis  of  the  road,  and 
the  base  of   all  field  operations.      Whenever  the  work  is 
going  on,  the  centre  pins  should  be  referred  to  fixed  points 
outside  of  the  ground  occupied  by  the  road. 

92.  The  first  operation  in  preparing  for  excavation  is  to 
place  side  stakt;s  at  one  half  the  width  of  road-bed  plus  the 
ditch,  on  each  side  of  the  centre  line. 

93.  Letting  out  slopes  is  a  term   applied  to  laying  off 
upon  the  ground,  on  each  side  of  the  centre,  the  distance  to 
which  the  slope,  commencing  at  the  outer  edge  of  the  ditch, 
will  extend,  depending  upon  the  angle  of  slope,  width  of 
road-bed  and  ditch,  and  depth  of  cutting.     There  are  here 
five  distinct  cases  which  may  occur :  — 

In  embankment  when  the  natural  surface  is  horizontal. 
In  embankment  when  the  natural  surface  is  inclined.  In 
excavation  when  the  natural  surface  is  horizontal.  In  exca 
vation  when  the  natural  surface  is  inclined. 

8* 
* 


90  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 

In  mixed  work  (side  hill,)  when  the  road-bed  is  partly  in 
cut  and  partly  in  fill.  In  both  excavation  and  embank 
ment,  when  the  natural  surface  is  horizontal,  we  have  only 
to  add  the  'cost,  in  feet  and  decimals,  multiplied  by  the 
slope,  to  one  half  the  width  of  road-bed  plus  ditch. 

Thus  suppose  the  cut  is    .         .  20.55  feet, 

half  the  road-bed,     ....  10.25     « 

ditch,    ......  3.00     " 

slope  1J  horizontal  to  1  vertical, 

and  we  have 

'      (20.55  X  li)  +  10.25  -f  3.0  =  44.075  feet. 

When  the  ground  is  inclined  transversely  to  the  axis  of 
the  road,  first  assume  a  point  upon  the  ground,  (apparently 
right,)  find  its  height  above  grade  with  the  level,  multiply 
this  by  the  slope  and  add  one  half  the  distance  between  the 
outer  edge  of  ditches,  and  see  how  near  it  comes  to  the 
measured  distance  from  the  centre  to  the  assumed  point ;  if 
within  a  foot,  it  will  answer ;  if  not,  a  second  trial  will  fix 
the  place. 

CULVERTS. 

94.  The  length  of  any  structure  passing  under  a  railroad 
embankment  is  L — 2  Rh,  where  L  is  the  distance  between 
slope  stakes,  R  inclination  of  slopes,  h  the  height  of  struc 
ture  from  the  natural  surface.  Thus,  suppose  the  distance 
between  slope  stakes  to  be  100  feet,  slope  1J  to  1,  and  h 
10  feet,  we  have 

L  —  100  —  (10  X  H  X  2)  —  100  —  30  =  70  feet. 

The  length  of  an  oblique  structure  will  of  course  be 
greater  than  that  of  one  at  right  angles  to  the  road ;  the 
length  depending  upon  the  obliquity. 


LAYING   OUT   WORK.  91 


MASONRY. 

95.  There  are  eight  general  cases  which  may  occur  in 
laying  out  such  structures  as  bridge  abutments  with  wings. 

1.  A  right  bridge  on  a  level  tangent, 

2.  A  right  bridge  on  a  level  curve, 

3.  A  skew  bridge  on  a  level  tangent. 

4.  A  skew  bridge  on  a  level  curve. 

5.  A  right  bridge  on  an  inclined  tangent. 

6.  A  right  bridge  on  an  inclined  curve. 

7.  A  skew  bridge  on  an  inclined  tangent. 

8.  A  skew  bridge  on  an  inclined  curve. 

And  these  eight  cases  will  vary  again  according  to  the  nat 
ural  surface  of  the  ground,  whether  horizontal,  or  inclined 
transversely. 

96.  The  general  position  of  wing  walls  and  general  form 
of  the  line  inclosing  the  base  of  the  bridge,  is  shown  from 
fig.  31  to  fig.  38.     Fig,  31  represents  case  one.     The  points 

Fig.  31. 


A,  B,  C,  D,  are  fixed  by  squares  from  the  centre  line  at 
E  F,  G  H. 


92  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Fig.  32  represents  case  two.     The  wings  3  c,  4  d,  must 

Fig.  32. 


evidently  have  a  different  inclination  from  A  1,  B  2.     The 
points  A,  B,  c,  c?,  1,  2,  3,  4,  as  before,  are  laid  off  by  squares 
from  a  tangent  to  the  curve. 
Fig.  33  explains  itself. 

Fig.  33. 


Fig.  34,  case  five.     Here  the  wings   A 1,   C  4,  are  the 

Fig.  T4. 


LAYING   OUT   WORK.  93 

same,  as  also  B  2,  D  3,  the  former  being  longer,  on  account 
of  the  greater  depth  of  the  fill. 

Fig.  35,  case   seven.      Here  each  wing  is  peculiar;    the 

Fi".  35. 


figure  being  a  compound  of  tig*.  33   uvi  3  t-. 

Figs.  36  and  37,  c;ise  8.     This  is  the  most  dl/IkuH;  of  :.•[!. 

F5«9.   37  imrl  38. 


94  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

No  two  wings  have  the  same  length  or  inclination  on  plan. 
The  natural  surface  being  horizontal,  the  line  inclosing  the 
bridge  is  A"B"C"D".  If  the  natural  surface  descended 
from  C"  to  A,  the  position  taken  would  be  A,  B,  C,  D.  Fig. 
37  is  the  elevation  of  the  position  A  B  C  D.  The  several 
points  are  laid  off  from  the  line  n,  n. 

The  general  manner  of  fixing  the  lines  of  figures  31  to  38, 
is  to  assume  the  angle  of  some  one  wing,  as  A  1,  in  fig.  34, 
to  draw  A  C  parallel  to  E  F ;  and  from  C,  the  intersection 
of  A  C  with  the  base  of  the  embankment,  C  4  gives  the 
other  wing.  Local  circumstances  will  of  course  often  fix 
at  once  the  length  and  angle  of  the  wings.  Upon  simple 
curves,  as  in  fig.  32,  the  lines  A  c  and  B  d  are  made  radial. 

97.  In  curving  a  viaduct,  the  axes  of  the  piers  are  made 
radial  to  the  centre  of  the  located  curve,  and  the  planes  of 
the  springing  lines  are  made  parallel  to  the  axes  of  the 
arches.     The  pier  thus  becomes  a  wedge,  and  should  be 
strengthened  by  a  starling,  upon  the  outside  of  the  curve, 
to  resist  the  resultant  of  the  thrusts  of  two  adjoining  arches. 

98.  We  should  never  try  to  stake  out  the  exact  horizon 
tal  projection  of  a  complicated  piece  of  work  upon  rough 
ground,  but  only  the  trenches,  which  being  cut,  give  a  hori 
zontal  surface  to  work  upon.     In  placing  the  stakes,  we 
must  be  careful  to  have  them  so  far  outside  of  the  work 
that  they  will   remain   undisturbed   while   operations   are 
going  on.     The  pegs  for  cutting  pits  and  trenches  may  be 
placed  at  the  angles  of  the  latter,  but  the  working  pegs 
must  be  so  placed  that  the  lines  stretched  from  one  to  the 
other  will  define  the  masonry.     All  measurements  made  in 
laying  out  work  should  be  made  by  graduated  rods,  and 
carefully  checked. 

99.  In  founding  piers,  and  in  aquatic  operations  gener 
ally,  two  stakes  upon  the  shore,  or  a  fixed  transit,  will  de 
fine  any  line  in  the  water.     Two  transits  will  define  points. 


LAYING   OUT  WORK.  95 

100.  A  permanent  beach  mark  should  be  carefully  fixed 
at  each  structure,  from  which  its  levels  may  be  obtained. 

101.  In  adjusting  oblique  bridges,  care  must  be  taken  to 
so  place  the  bridge  seats  that  the  floor  beams  shall  lie  in  a 
correct  plane,  and  not  be  at  all  warped  or  winding. 

102.  As  an  example  of  laying  out  work  with  regard  to 
heights,  take  the  case  of  fig.  38.     Let  the  grade  of  the  cen- 

Fig.  38. 


tre  line  be  one  in  100,  the  angle  of  obliquity  45°,  the  width 
of  bridge  twenty  feet,  and  span  on  the  skew  one  hundred 
feet.  Required  the  elevations  of  the  points  A,  B,  C,  D. 

Assume  the  height  of  (2)  as          ....  100.00 

That  of  (3)  will  be 99.00 

b,  being  10  feet  back  of  2,  is      .         .         .         .  IQQMf     I  # 

and  d  0.1  feet  less  than  (2)  or          ....  99.90 

also  a  =99.00  +  0.10,  or    ....         .  99.10 

and  c  =  99.00  —  0.10,  or 98.90. 

TUNNELS. 

103.  The  maintaining  a  correct  centre  line  through  tun 
nels  is  generally  considered  difficult.  The  fixing  of  the  line 
in  deep  shafts  requires  great  care,  owing  to  the  short  dis 
tance  between  the  only  two  fixed  points,  that  can  be  trans 
ferred  from  the  surface  to  the  bottom  of  the  pit.  This  is  a 
matter  of  manual  skill  and  of  instrumental  manipulation. 


96  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 

There  is  no  difficulty  in  aligning  the  upper  ends  of  two 
plumb-lines ;  and  the  lower  ones  will  certainly  be  governed 
by  their  position.  The  following  method  has  been  found 
to  answer  every  purpose. 

Let  the  opening  of  the  shaft  be  ten  feet  in  diameter. 
Place  two  horizontal  bars  at  right  angles  to  the  road  across 
the  opening,  upon  which  slide  blocks  holding  the  upper  end 
of  the  plumb-lines.  Adjust  these  lines,  at  the  surface,  with 
a  transit ;  and  when  fixed,  place  iron  pins  at  the  point 
marked  by  the  plumbs  at  the  bottom  of  the  shaft.  Upon 
these  pins  fix  the  exact  centres.  For  keeping  the  line  in 
the  shaft  headings,  a  straight  rod,  with  steel  points  at  each 
end,  should  be  used,  which  being  placed  upon  the  iron  cen 
tre  pins,  fixes  the  centre  line  of  the  tunnel.  When  the  tun 
nel  is  curved,  the  line  should  be  laid  off  by  offsets  from  the 
tangent  to  the  curve  at  the  shaft. 

By  this  method  points  at  ten  feet  distance  may  be  fixed 
within  T-J<y  of  an  inch,  a  difference  of  which  would  cause 
an  error  of  ^  of  an  inch  per  one  hundred,  or  an  inch  per 
thousand  feet, 


CHAPTER    VI 


EARTHWORK. 


104.  -THE  reader  is  presumed  to  be  acquainted  with  the 
manner  of  finding  the  areas  and  cubes  of  simple  geometric 
figures  and  bodies.  The  following  fifteen  figures  show  the 
forms  which  may  be  taken  by  the  cross  section  of  a  rail 
road  in  cutting ;  for  embankment  invert  the  same.  They 
are  easily  separable  into  simple  figures. 


Fig.  40. 


Fig.  39. 


98 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 
Pig.  43.  Fig.  44. 


Fig.  45. 


Fig.  46. 


Fig.  47. 


Fig.  48. 


EARTHWORK. 


99 


Pig.  49. 


Fig.  50. 


Fig.  54. 


105.  The  formation  of  tables  for  the  amount  of  earth  in 
level  cutting  is  very 
simple.  The  area 
of  the  following  sec 
tion,  where  B  is  the 
base,  and  R  the  hor 
izontal  dimension  of 
the  slope,  is 


X*,  or 


or  finally 


100  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

i.  e.,  the  base  of  a  rectangle  by  its  height.  Multiply  this  by 
100  and  divide  the  product  by  27  ;  or  divide  by  T2oV,  and  we 
have  the  cubic  amount  in  a  prism  one  hundred  feet  long. 
The  road-bed  being  nineteen  feet  wide,  and  slopes  one  and 
a  half  to  one,  the  formula  for  the  amount  of  a  prism  one 
hundred  feet  long  is 


0.27 


and  assuming  the  base  of  rock  cutting  as  eighteen  feet, 
and  slope  one  quarter  to  one,  and  embankment  eighteen 
feet  at  subgrade,  we  have,  rock, 


(72  +  h) 
1.08 


and  embankment, 


0.27 


the  figure  being  inverted  for  embankment.  For  a  prism 
of  ten  or  of  one  thousand  feet  in  length,  we  have  only  to 
move  the  decimal  point.  In  forming  a  table,  proceed  as 
follows :  — 


0.27 

a  b  c  d 

a'  b'  c'  df 

an  bn  c*  dn. 


EARTHWORK.  101 

It  is  evident  from  inspection  of  fig.  55,  that  c  exceeds  c° 

Fig.  55. 


by  h  X  2  r ;  and  that  c"  exceeds  c'  prime  by  h'  X  2  / ;  and 
so  on  as  far  as  we  go ;  this  increase  being  constant,  we 
have  then  to  find  the  area  of  c,  and  for  the  area  c  -\-  c' 
double  c,  and  add  the  increment ;  whence  the  rule  :  — 

Having  found  the  increase  (which  varies  with  the  angle 
of  the  slope)  for  the  second  section,  add  the  increase  to 
twice  the  first.  For  the  third)  add  twice  the  increase  to 
three  times  the  first ;  and  for  the  wth,  add  n  —  1  times  the 
increment  to  n  times  the  first  area,  or  algebraically  calling 
a  the  first  area,  a'  the  second,  d'  the  third,  an  the  nth  area, 
and  we  have 
j^rj,*,(».  ^  t<»;'  <*  *•  » f v 

The  first  area  a        =  a ; 

The  second  area  2  a  -\-  i        =  a' ; 

The  third  area  3  a  -f-  2  i        =  a" ; 

The  wth  area      na-\-(n  —  1)  i        =  an. 

We  might  operate  at  once  upon  the  cubic  contents,  but  for 
the  length  to  which  some  decimals  run ;  some  indeed  cir 
culating. 

106.    The   table  thus   made   may  be   of  the   following 
form :  — 

9* 


102 


HANDBOOK   Otf  RAILROAD   CONSTRUCTION. 


Cut  (or  fill),  Cubic  yards  Earth.  Cubic  yards  Bock. 

in  feet.  Slopes  1|  to  1.  Slopes  J  to  1. 

1  76  68 

2  163  137 

3  261  208 

4  371  282 

5  491  356 

6  622  433 

7  802  512 

8  919  593 

9  1083  675 
10                         1260                             759 

i.  e.,  cut  being  eight  feet,  each  one  hundred  feet  length  gives 
nine  hundred  and  nineteen  cubic  yards ;  one  thousand  feet, 
9190  yards,  and  ten  feet  of  length  91.9  cubic  yards. 

107.  The  preceding  system  is  intended  only  for  approxi 
mate  estimates.     Let  one  person  read  off  the  cuts  or  fills 
from  the  profile,  a  second  give  the  corresponding  number 
of  yards  by  the  table  made  as  above,  while  a  third  sets  the 
figures  down ;   being  careful  to  separate  the  cuts  from  the 
fills. 

For  final  measurements,  none  but  the  prismoidal  formula 
should  be  used ;  the  length  of  the  prismoids  being  taken 
at  each  one  hundred  feet,  and  nearer  when  the  ground  is 
rough. 

108.  As  an  example  of  the  comparative  amounts  given 
by  the  above   formula,  and  by  the   common  method   of 
averaging  end  areas,  take  the  following,  the  slopes  being 
li  to  1. 

Base.  Distance.  Cut.  End  Area!  Mean  Area.       Middle  Area. 


20 

0 

0 

000 

000 

000 

20 

50 

5 

137 

069 

059 

20 

50 

10 

350 

244 

236 

20 

50 

15 

637 

493 

483 

20 

50 

00 

000 

318 

236 

EARTHWORK.  103 


By  averaging  end  areas  we  have 


50  X  69—  3,450 
50  X  244  =  12,200 
50  X  493  =  24,650 
50  X  318  =  15,900  Sum,  56,200. 

And  by  the  prismoidal  formula, 

50  X  305 
50  X  1,257 
50  X  2,669 
50  X  1,755  Sum  299,300  -^-  6  ==  49,000, 

and  56,200  —  49,000  =  7,200 

cubic  feet  in  favor  of  the  method  of  end  areas. 
109.    The  prismoidal  formula  is  algebraically 


when  L  =  length, 

c  =  cubic  contents, 
a  =  area  of  one  end, 
a'  =  area  of  other  end, 
a"  =  middle  area  ; 

or,  verbally,  to  the  sum  of  the  end  areas  add  four  times  the 
middle  area,  and  multiply  the  result  by  one  sixth  of  the 
length;  the  middle  area  being  the  area  made  upon  the 
mean  height  of  the  two  ends.  Thus  if  the  length  is  one 
hundred  feet,  and  ten  feet  high,  the  other  twenty  feet  high, 
and  slopes  one  and  a  half  to  one.  the  cubic  amount  is,  (the 
base  being  twenty-two  feet,) 


x  100  . 


104  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


EXCAVATION   AND    EMBANKMENT. 

110.  Some  writers  have  considered  that  the  grades  of 
a  road  should  be  so  adjusted  as  to  equalize  the  cutting 
and  the  filling.     The  total  rise  and  fall  might  not  be  much 
affected  by  this,  but  the  mechanical  effect  of  grades  might. 
A  perfect  balance  between  the  cuts  and  fills  is  not  to  be 
desired.     The  whole  cost  of  earthwork  must  be  a  mini 
mum,  and  it  is  often  cheaper  to  waste  and  borrow,  than  to 
make  any  long  hauls,  and  to  form  the  grade  line  by  in 
terchange  of  material  on  the  profile  only. 

111.  The  transverse  slopes  depend  upon  the  nature  of 
the  soil  in  which  the  cut  is  made.     Gravel  will  stand  at  a 
slope  of  one  and  a  half  horizontal  to  one  vertical,  and  in 
some  cases  one  and  a  quarter,  or  even  one  to  one.     Clay 
stands  nearly  vertical  for  some  time,  but  finally  assumes  a 
very  flat  slope,  in  some  cases  two,  three,  and  even  four  hori 
zontal  to  one  vertical.     In  places  where  a  stratum  of  clay 
underlies  more  reliable  earth,  to  avoid  a  very  long  slope,  it 
may  be  economical  to  support  the  clay  by  a  wall,  and  to 
slope  the  earth  only. 

112.  Care  should  be  taken  in  every  case  to  secure  good 
drainage  and  to  protect  the  slopes  by  surface  drains  at  the 
top.     The  drains  in  long  cuts  should  be  slightly  inclined  to 
insure  the  running  off  of  the  water.     A  fall  of  ten  feet  per 
mile  is   enough ;    five  will    answer  in  many  cases.      On 
side  hill  cuts  a  surface  drain  along  the  top  of  the  upper 
slope  will  do  good  service.     On  many  high  embankments, 
catchwater  drains,  commencing  at  the  road-bed  and  gradu 
ally  sloping  to  the  base,  will  prevent,  in  a  great  degree,  cut 
ting  of  the  bank. 

113.  Embankments,  when  made  rapidly,  should  be  fin 
ished  to  the  full  width,  somewhat  above  true  grade,  to  allow 
for  the  after  settlement.     (See  specification.) 


EARTHWORK. 


105 


114.    The  following  allowances  have  been  made  for  the 
shrinkage  of  material  in  some  parts  of  America. 


Light,  sandy  earth 
Clayey  earth 
Gravelly  earth   . 
Gravel  and  sand 
Loam 
Clay      . 
Clay  puddled 
Wet  surface  earth 


0.12 
0.10 
0.08 
0.09 
0.12 
0.10 
0.25 
0.15 


The  bulk  of  quarried  rock  on  the  contrary  increases  from 
twenty-five  to  fifty  per  cent. 

115.  When  embankments  are  carried  up  slowly,  in  lay 
ers  of  three  or  four  feet  at  a  time,  the  after  settling  is  very 
little ;  when  carried  up  all  at  once  it  will  be  more.  The 
full  width  must  Fig.  56. 

be  kept,  even 
above  the  required 
height.  Fig.  56 
shows  the  forms 
of  a  bank  both 
before  and  after 
settlement. 

The  best  method  of  forming  a  bank  of  bad  material  is  to 
ram  the  layers  as  in  fig.  57 ;  thus  the  tendency  is  to  consol 
idate  by  settling,  and  not  to  destroy  the  work  by  sliding. 

Fig.  57. 


106  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


TRANSPORT    OF    MATERIAL. 

116.  In  the  formation  of  embankments  it  is  not  always 
advisable  to  make  the  whole  bank  from  an  adjoining  cut  or 
cuts.     The  length  of  haul  may  be  too  long.     In  this  case 
it  is  customary  to  waste  a  part  of  the   cut  and  to  borrow 
earth  from  some  nearer  point  for  the  bank.     That  the  trans 
port  shall  be  effected  in  the  most  economical  manner,  the 
product  of  the  cube   of  earth,  by  the   mean  distance,  (the 
distance  between  the  centres  of  gravity,  of  excavation  and 
embankment)   must  be   a  minimum.      To    determine   the 
theoretical  minimum   expense,  the  problem  becomes  very 
complicated   on    account  of  the  great  number  of  variable 
elements  entering  therein ;  and  the  result  obtained  is  appli 
cable  only  to  a  particular  case.     Local  circumstances  more 
than  any  other  thing,  determine  the  position  of  a  borrow 
pit,  and  the  path  over  which  the  material  is  to  be  trans 
ported. 

OF    THE    AVERAGE    HAUL. 

117.  To  find  the  cost  of  the  movement  of  earth  on  any 
section,  we  must  have,  the  total  amount  of  earth  to  be 
moved,  and  the  average  haul;  the  latter  being  the  distance 
through  which,  if  the  whole  amount  were  moved,  the  cost 
would  be  the  same  as  the  sum  of  the  costs  of  moving  the 
partial   amounts  their  respective  distances.      To  find  the 
average  haul  proceed  as  follows:  First,  find  the  distance 
between  the  centres  of  gravity  of  each  mass  bofh   before 
and  after  moving,  which  may  be  done  with  sufficient  accu 
racy  for  practice  by  inspection  of  the  profile.     Next, 

118.  Divide  the  sum  of  the  products  of  the  partial  amounts 
by  their  respective  hauls,  by  the  total  amount;  the  result  is 
the  average  haul  in  feet.     Or  algebraically,  representing  the 
partial  amounts  by  m,  m',  m",  mf",  the  respective  hauls  by 


EARTHWORK.  107 

d,  d',  d",  dnr,  the  total  amount  by  S,  and  the  average  haul 
by  D,  we  have 

md  +  m't?  +  m"  d"  -f  m"'  d"'  _ 

Example.  —  Let  column  1  show  the  partial  amounts  in 
cubic  yards.  Column  2  the  corresponding  hauls. 

1,000  X  200=  200,000 
2,000  X  300  =  600,000 
5,000X400  =  2,000,000 
8,000  X  600  =  4,800,000 

16,000  7,600,000 

7,600,000 

and   -=  „  AnA-=  475  feet  average  haul. 
1 6,000 

Proof.  —  Assume  the  cost  of  moving  1,000  yards  one  foot 
as  ten  cents,  the  costs  of  the  separate  masses  are 

1,000  yards  200  feet  is  $20.00 

2,000      "      300     "  60.00 

5,000      «      400     «  200.00 

8,000      "      600     «  480.00 

Sum,  $76aOO~ 

also  the  cost  of  moving  16,000  yards  475  feet  is 
16  X  475  X  10  =  $760.00. 

119.  The  movement  of  earth  is  effected  by  shovels,  bar 
rows,  horses  and  carts,  or  by  cars.  In  round  numbers  we 
can  move  earth 

By  shovels  alone    .         .         .         .  10  to       20  feet, 

By  barrows  alone  .  .  .  .  20  to  100  " 
By  carts  .  .  .  .  .  100  to  500  " 
By  cars 500  to  5,000  " 


108  HANDBOOK   OP  RAILROAD   CONSTRUCTION. 

As  the  haul  increases,  the  number  of  vehicles  of  trans 
port  remaining  the  same,  the  number  of  excavators  must 
decrease.  Earths  easily  removed  do  not  admit  of  so  large  a 
haul,  with  a  given  number  of  excavators,  as  hard  earths. 
The  nature  of  the  ground,  form  of  carts,  kind  of  horses, 
season  of  the  year,  and  price  of  labor  are  some  of  the  ele 
ments  entering  the  problem  of  transport.  The  best  illus 
tration  of  the  matter  will  be  found  among  the  very  able 
writings  of  Elwood  Morris,  Esq.,  C.  E.,  in  the  Journal  of 
the  Franklin  Institute.  Knowing  the  value  of  wages,  the 
nature  of  the  earth  and  length  of  haul,  it  is  easy  to  see 
what  mode  of  transport  must  have  the  preference. 


CONTRACTOR'S   MEASUREMENTS. 

120.  The  price  of  executing  any  piece  of  work  is  paid 
to  the  contractor  at  stated  intervals,  generally  once  each 
month.  The  amount  of  work  done  at  these  partial  pay 
ments  is  obtained  by  instrumental  reference  to  the  ground. 
Towards  the  completion  of  operations  the  most  correct  and 
easiest  method  of  finding  the  rate  of  progress  is  to  deduct 
the  amount  already  done  from  the  total  as  given  by  primary 
measurement.  The  full  price  is  not  paid  to  the  contractor, 
but  a  percentage  is  kept  back,  which  insures  a  faithful  per 
formance  of  work.  It  is  impossible  to  establish  a  pro  rata 
price  at  first,  owing  to  the  uncertain  nature  of  the  work ; 
what  appears  to  be  earth  may  be  rock.  By  deducting  a 
maximum  price  estimate  for  all  but  one  of  the  items,  an 
approximate  pro  rata  value  for  that  one  may  be  determined. 
An  analysis  of  cost  will  define  the  minimum  limit  for  ad 
vantage  to  the  contractor ;  and  the  pro  rata  value  less  the 
percentage,  the  maximum  for  the  company's  benefit. 


EARTHWORK.  109 


DRAINING. 

121.  "When  a  level  is  to  be  drained,  or  the  water  carried 
off  from  the  surface  of  a  swamp,  the  first  point  to  be  ascer 
tained  is  the  location  of  the  lowest  outfall.  The  direction 
in  which  aquatic  plants  lie  show  the  natural  fall  of  the 
water,  these  always  pointing  down  stream.  When  the 
most  available  outlet  has  been  decided  upon,  a  main  drain 
should  be  set  out,  from  which  oblique  branches  are  to  be 
cut,  pointing  in  the  direction  of  the  current ;  into  these  all 
minor  cuts  are  to  be  collected  so  that  the  whole  district  may 
be  equally  drained.  The  fall  should  be  greatest  at  the  most 
remote  points,  decreasing  as  the  amount  of  water  increases. 
Large  and  deep  rivers  run  sufficiently  fast  when  the  fall  is 
one  foot  per  mile.  For  small  rivers,  double  that  is  neces 
sary.  Ditches  and  ordinary  drains  require  eight  feet  per 
mile.  When  the  water  is  made  to  pass  away  from  the  sur 
face,  it  should  flow  very  gradually,  that  the  sides  and  bot 
tom  of  the  ditches  may  not  be  worn  away  by  friction  ;  it 
should  be  in  constant  motion  that  the  channel  may  be  kept 
clean  and  increase  in  velocity  as  it  proceeds.  When  the 
surface  is  a  perfect  level,  the  drains  should  of  course  be 
made  straight. 

After  the  quantity  of  water  has  been  determined  by  care 
ful  observation,  the  section  of  the  main  and  branches  must 
be  fixed,  so  that  regarding  both  their  areas  and  velocities, 
the  main  drain  will  not  be  overcharged. 

To  facilitate  the  current,  the  sides  should  be  inclined 
about  one  and  a  quarter  to  one ;  and  the  breadth  of  base 
should  be  two  thirds  of  the  depth  of  water.  These  results 
are  obtained  from  the  practice  of  English  engineers,  who 
have  given  a  great  deal  of  attention  to  the  subject. 

10 


110  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 

Drains  cut  through  bogs,  may  have  sides  nearly,  if  not 
quite  vertical,  as  the  fibres  of  plants  forming  the  soil  resist 
the  action  of  the  water. 


SUBSOIL    DRAINING. 

Geology  has  assisted  this  operation  very  materially  by 
rendering  us  acquainted  with  the  quality  and  nature,  as 
well  as  of  the  succession  of  strata.  The  soils  which  are 
impervious  are  usually  the  heaviest,  and  the  porous  are 
those  of  lighter  quality.  Clays,  when  they  receive  water, 
will  only  part  with  it  by  evaporation,  when  left  in  a  natural 
state ;  and  therefore  to  make  such  a  surface  fit  for  a  useful 
end  requires  considerable  ingenuity,  and  often  great  ex 
pense.  Such  a  soil  is  not  rendered  unstable  by  underground 
springs,  and  may  be  effectually  drained  by  boring  through, 
and  letting  the  water  off  into  an  under  stratum,  when  this 
is  of  a  porous  nature. 

When  land  abounds  with  springs,  or  is  subject  to  the 
oozing  out  of  subterraneous  water,  draining  is  effected  in  a 
different  manner.  Springs  have  their  origin  in  the  accumu 
lation  of  rain  water,  which  falling  upon  the  earth,  after 
passing  the  porous  strata,  lodges  upon  the  impervious,  and 
glides  along  the  sloping  surface  until  it  crops  out,  generally 
in  some  valley  where  it  forms  a  watercourse. 

Descending  streams  are  easily  taken  care  of  by  collect 
ing  them  into  a  body  before  they  reach  the  low  lands. 

When  a  morass  is  to  be  drained,  the  strata  upon  which 
it  reposes  should  be  examined,  and  if,  as  is  often  the  case,  a 
layer  of  clay  intervenes  between  the  substratum  and  the 
mossy  covering,  which  holds  the  water,  by  tapping  this  in 
well  chosen  places,  the  whole  will  sink  away. 

A  fine  example  of  embankment  upon  a  bad  bottom  was 


EARTHWORK.  Ill 

performed  by  Mr.  Stephenson,  on  the  Great  Western  Rail 
road,  England,  at  the  crossing  of  Chatmoss.  This  moss 
was  so  soft  that  cattle  could  not  walk  upon  it,  and  an  iron 
bar  sank  into  it  by  its  own  weight.  The  moss  was  first 
thoroughly  drained  by  a  system  of  longitudinal  and  cross 
drains,  and  the  embankment  made  of  the  lightest  material 
possible  —  the  dried  moss  itself.  Without  this  treatment, 
the  moss  would  have  sank  beneath  the  bank  alone ;  it  now 
supports  the  passage  of  the  heaviest  railroad  trains. 

METHOD   OF   CONDUCTING  OPERATIONS. 

122.  The  organization  of  the  engineer  corps  upon  a  rail 
road  is  as  follows,  differing  somewhat  in  different  parts  of 
the  country. 

The  Chief  Engineer  has  entire  charge  of  all  the  work,  of  all 
assistants,  appointing  and  dismissing  members  of  the  corps, 
designing  of  all  structures,  making  of  specifications,  and  of 
all  mechanical  operations  incident  to  the  thorough,  correct, 
and  timely  construction  of  the  road ;  and  should  be  able 
also  to  specify,  generally,  the  amount  and  character  of  the 
equipment  needed. 

The  Resident  Engineer  has  charge  of  the  detailed  con 
struction  of  from  twenty-five  to  fifty  miles  of  road,  accord 
ing  to  the  nature  of  the  work,  being  responsible  to  the  chief 
engineer  for  the  proper  execution  of  the  orders  from  head 
quarters  ;  he  returns  to  the  chief  engineer  a  monthly 
account  of  the  exact  condition  of  his  work,  both  as  to  the 
amount  executed,  and  also  that  remaining  to  be  done. 

The  assistants  of  the  resident  engineer  are  a  leveller 
and  transit  man ;  to  whom,  under  his  supervision,  is  the 
duty  of  laying  out,  measuring,  and  estimating  the  work. 
The  leveller  has  with  him  one  or  more  rodmen.  The 
transit  man,  two  chainmen,  and  one  or  more  axemen. 


112  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

In  some  cases,  added  to  the  above  are  inspectors  of  ma 
sonry,  bridging,  and  superstructure.  These  are  necessary 
only  when  the  road  embraces  a  great  number  of  mechani 
cal  structures ;  too  many  to  leave  the  proper  time  to  the 
resident  engineer  for  his  other  duties.  Once  each  month 
the  exact  amount  of  graduation,  bridging,  and  masonry 
executed  is  obtained  by  the  resident  and  his  assistants.  The 
chief  engineer  applies  the  prices  to  these  amounts,  and  the 
percentage  deduction  being  made,  the  estimate  is  ready  for 
the  treasurer. 

123.  The  abstract  prepared  from  the  monthly  estimate 
should  show  clearly,  without  unnecessary  figures,  the 
amount  of  work  completed,  and  also  that  remaining  to  be 
done. 

For  convenience,  the  various  blanks  used  on  railroads 
should  fold  to  the  same  form  and  size.  The  blanks  are, 

The  Contract, 

The  Specification, 

The  Resident  Engineer's  Monthly  Return, 

The  Assistant's  Weekly  and  Monthly  Returns, 

The  Force  Return, 

The  Pay  Roll, 

Vouchers. 

The  contract  and  specification  are  given  in  chapter  IV. 
The  resident's  monthly  return  to  the  chief  engineer  is  some 
what  as  follows :  — 

Monthly  return  of  work  done  on  the  first  division  of  the 

A  and  B  Railroad,  for  the  month  ending ,  showing  also 

the  whole  amount  of  work  up  to ;  also  the  present 

estimate  for  completion. 


EARTHWOKK, 


113 


1 

p 

GRADUATION. 

Clearing  and  Grubbing. 

Excavation. 

In  July. 

Total  to  date. 

In  July. 

Total  to  date. 

Acres. 

Price. 

Am't. 

Acres. 

Pr. 

Am't. 

Yards. 

Pr. 

Am't. 

Yards. 

Pr. 

10 

Am't. 

15 

100 

1500 

300 

100 

30000 

44000 

10 

4400 

100000 

10000 

MASONRY. 

First  Class. 

Second  Class. 

Third  Class. 

Foundation  in 
Excavation. 

Foundation 
Timber. 

In 
July. 

Total  to 
date. 

In 
July. 

Tot.  to 
date. 

In 
July. 

Tot.  to 
date. 

In 
July. 

Tot.  to 
date. 

In 
July. 

Tot.  to 
date. 

Yds. 

Pr. 

Am't. 

Yds. 

Pr. 

Am't. 

V 

BRIDGING   AND    TIMBERWORK. 

Truss  Bridges. 

In  July. 

Total  to  date.           Pile  Bridges. 

Stringer  Bridges. 

Trestling. 

Feet. 

C. 

Am't. 

Fee, 

C. 

Am't. 

SUPERSTRUCTURE    AND    FENCING, 

Superstructure. 

Fencing. 

In  July. 

Total  to  date. 

In  July. 

Total  to  date. 

Miles. 

Price. 

Am't. 

Miles, 

Price. 

Am't. 

10 


114 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


VALUE   OF    WORK   AND   PAYMENTS   MADE. 

Value  of  Work 
In  July. 

Amount  paid 
in  July. 

Whole  value 
to  date. 

Whole  amount 
paid. 

Amount  left 
due. 

VALUE    OF    LABOR. 

Foreman  and 
Mechanics. 

Laborers. 

Carts  with 
Horses. 

Carts  with 
Oxen. 

Whole  value. 

RECAPITULATION. 

Value  of  work 
done  in  July. 

Value  of  work 
up  to  date. 

Remaining 
Value. 

The  resident  engineer's  assistants  return  to  him  weekly  a 
statement  of  the  amount  and  value  of  the  force  employed 
upon  the  several  sections,  and  monthly  the  exact  amount  of 
work  done  on  the  same,  for  each  of  which  there  should  be 
a  blank.  The  above  forms  may  be  printed  and  folded  in 
8vo.,  or  may  be  the  continuous  headings  of  a  large  sheet. 


CHAPTER   VII. 

ROCKWORK. 


125.  THE  sides  of  rock  excavation  are  sometimes  cut  to 
a  small  slope,  as  one  fourth  or  one  fifth  horizontal  to  one 
vertical,  and   sometimes   cut  quite  perpendicularly.      The 
earth,  when  it  occurs,  which  covers  the  rock,  is  first  taken 
out  at  the  proper  slope  ;    a  loam  of  one  or  two  feet  being 
left  between  the  foot  of  the  earth  and  the  crest  of  the  rock. 

126.  Rock  is  taken  out  one  or  two  feet  below  grade,  as 
well   as  earth,  to  allow  the  introduction  of  the  necessary 
ballast. 

127.  The  most  common  mode  of  removing  rock  is  by 
blasting ;  for  this  holes  are  drilled  by  steel-edged  jumpers, 
worked   either   by  hand  or   by  steam.     The  first  object  in 
cutting  a  passage  through  rock,  is  to  open  a  working  face, 
so  as  to  get  the  necessary  lines  of  least  resistance,   (this 
line  is  that  by  which  the  powder  finds  the  least  opposition 
to  a  rent  at  right  angles  to  the  length  of  the  drill) ;  these 
lines  should,  if  possible,  be  at  right  angles  to  the  beds  of 
stratification ;    the  holes  should  be  drilled  parallel  to  the 
seams  of  the  rock,  as  the  powder  will  then  lift  off  the  strata. 
In  working  a  vertical  face,  it  may  be  best  to  blast  out  the 
lower  part  first,  and  so  undermine  the  overhanging  mass. 


116  HANDBOOK   OF  RAILROAD  CONSTRUCTION. 

128.  The  amount  of  powder  in  different  charges  to  pro 
duce  proportional  results  should  be  as  the  cube  of  the  line 
of  least  resistance  ;  for  example :  — 

23  is  to  4oz.  as  33  is  13^oz., 
or 

8  to  4  as  27  to  13J; 

and  generally, 

L3  :  w  ::  LfS  :«/; 
whence 

w  L's 
™f  =   -JIT. 

129.  The   following   charges  corresponding  to   lines  of 
least  resistance  are  from  the  works  of  Sir  John  Burgoyne. 

Line  of  least  resistance.  Charge  of  powder. 

2  feet,  0  Ibs.  4  oz. 

4    "  2  "     0  " 

6     "  6  "  12  " 

8     "  16  "     0  " 

130.  After  the  powdered  stone  is  removed,  the  powder  is 
placed  in  the  lower  part  of  the  hole ;  after  which  a  wad  of 
turf,  or  some  other  light  material,  follows  ;    next  the  tamp 
ing  of  powdered  brick,  dried  clay,  or  something  similar,  and 
finally  a  stopper  of  wet  clay,  or  some  other  firm  substance. 
A  hole  is  left  through  all,  communicating  with  the  powder 
by  ramming  the  tamping  around  a  wire  ;  through  this  hole 
a  fuse  is  inserted  by  which  to  light  the  charge.     The  most 
perfect  tamping  would  offer  a  resistance  as  great  as  that  by 
the  natural  rock.     A  great  improvement  upon  the  above 
method  is  the  sand  blast ;   the  powder  is  put  in,  and  the 
hole  filled  with  loose,  dry  sand,  simply  poured  in  and  set 
tled  by  a  gentle  stirring,  but  not  at  all  rammed ;  the  explo 
sion  of  the  powder  spreads  the  sand  as  a  wedge,  and  causes 


ROCKWORK.  117 

the  power  of  the  blast  to  be  exerted  sideways.  In  some 
cases  a  small  cone  of  wood  has  been  placed  (base  down) 
in  the  hole  with  the  sand,  which  aids  very  much  in  stop 
ping  the  exit  of  the  blast  through  the  drill. 

131.  Of   late   years   an   admirable   method  of   lighting 
large  charges  simultaneously  has  been  employed,  namely, 
volcanic  electricity. 

132.  A   gigantic   example    of    the   application   of    this 
method   has  been  furnished  by  the   English  engineers  in 
overthrowing  a  portion  of  Round  Drum  Cliff,  about  two 
miles  from  Dover,  (England).    Two  chambers,  13  X  5J  ><  4J, 
and  one  10  x  5J  X  4  feet  were  cut  in  the  rock.     Within 
these  were  placed  fifty  bags  of  powder,  amounting  in  all 
to    eight  and  one  half  tons.      The   charges  were  lighted 
by  the  voltaic  system,  by  which  operation  a  mass  of  rock 
(chalk)  380  ><  360  X  80  feet,  amounting  to  400,000  cubic 
yards,  was  thrown  into  the  sea,  and  by  which  there  was  es 
timated  to  have  been  saved  nearly  $40,000. 

133.  The  following  table  from  Colonel  Puseling's  mem 
oranda  on  mining,  shows  the  capacity  of  different  drills  for 
powder,  by  weight,  and  also  the  depth  of  holes  of  different 
diameters,  to  contain  one  pound  of  powder. 

Diameter  of  hole        Ounces  of  powder  in  Powder  in  one  Depth  of  hole  in  inches 

in  inches.  one  inch  depth.  foot  deep.  to  contain  one  pound. 

Ibs.        oz. 

1  0.4  0  5.0  38.2 
1J  0.9  0  11.3  16.9 

2  1.7  1  4.1  9.5 
2-J  2.6  1  15.4  6.1 

3  3.7  2  13.2  4.2 
31  5.1  3  13.5  3.1 

4  6.7  5  0.4  2.4 
41  8.4  6  5.7  1.9 

5  10.5  7    13.6  1.5 
5J-                     12.7                   9      8.0  1.3 

6  15.1  11      4.9  1.0 


118 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


134.  Blasting  under  water  has  been  practised  to  some 
extent,  and  with  great  success  by  Messrs.  Maillefaut  and 
Raasloff,  both  in  New  York  harbor  and  in  the  St.  Law 
rence  River.  The  method  is  merely  to  explode  bodies  of 
powder  upon  the  surface  of  the  rock,  the  water  itself  being 
a  sufficient  source  of  reaction  to  the  blast. 


TUNNELLING. 

135.  Tunnels  are  driven  through  hills  to  avoid  very 
deep  cutting.  When  in  rock  of  a  solid  nature,  the  roof  sup- 
Fig.  58.  ports  itself ;  but  when  in 
earth  or  in  loose  rock,  an 
artificial  arched  lining  be 
comes  necessary.  Figs. 
58  and  59  show  sections 
in  both  rock  and  earth  ; 
the  insert  b  b  is  placed  in 
a  bed  of  concrete.  In  ex 
cavating  earth,  a  tempo 
rary  roof  is  made  -use  of 
while  the  work  is  in  pro 
gress,  which  is  afterwards 
replaced  by  an  arch  of 
brick  or  stone.  The  back 
of  the  arch  must  be  closely 
wedged,  quointed,  and  the 
earth  well  rammed  in. 

The  great  disadvantages 
attending  the  construction 
of  tunnels  are  want  of  air, 
light,  room,  and  drainage. 
To  facilitate  the  latter  re 
quirement,  a  very  light 


KOCKWORK.  119 

grade  may  be  introduced  ;  this  may  easily  be  done,  as  they 
generally  occur  on  summits,  or  on  the  approach  to  sum 
mits  ;  ToV F  or  nve  fee^  Per  mile  is  sufficient. 

In  working  a  tunnel  which  is  upon  a  grade,  one  end  nat 
urally  drains  itself  if  the  approach  is  taken  out ;  the  other 
drains  the  wrong  way,  to  meet  which  obstacle  we  must  re 
sort  to  pumps  which  follow  the  work,  keeping  always  in 
the  lowest  place,  or  by  sinking  a  well  at  the  shaft  through 
which  the  water  is  raised  to  the  surface. 

The  ventilation  of  tunnels  is  effected  by  drawing  off  the 
bad  air  when  a  fresh  supply  must  enter. 

136.  In  taking  out  the  rock,  the  expense  will  depend 
much  upon  the  nature  and  stratification  of  the  rock  en 
countered. 


SHAFTS. 

137.  In  tunnels  of  considerable  length,  a  long  time  would 
be  consumed  in  working  from  the  ends  only.    In  such  cases 
it  is  customary  to  sink  shafts  at  the  most  convenient  places 
(the  shallowest  when  at  the  proper  distance,)  and  to  com 
mence  at  the  bottom  of  these  to  work  both  ways.     This 
operation  involves  considerable    expense,  as   all   draining, 
ventilating,  and  removal  of  excavated  materials  must  be 
effected  through  the  shaft. 

In  leaving  openings  for  the  exit  of  smoke  and  for  admis 
sion  of  light  in  artificial  arches,  regard  must  be  had  to  their 
position.  They  should  be  at  the  springing  rather  than 
at  the  crown  of  the  arch,  as  they  will  thus  less  affect  the 
strength  of  the  masonry. 

The  approaches  of  tunnels  in  cities  and  in  other  places 
where  appearance  is  of  importance,  are  furnished  with  face 
coping  and  wings. 

138.  Tunnels,  when  conducted  in  the  most  expeditious 


120 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


manner,  require  for  their  completion  a  long  time.  The  fol 
lowing  table  shows  the  rate  of  progress  upon  some  of  the 
most  important  tunnels  of  America. 


Name  of  Tunnel.  Le 

*Penn  Railroad, 
*Kingwood  B.  &  O.  R.  R. 
Board  Tree  B.  &  0.  R.  R. 
*  Welling,  B.  &  0.  R.  R. 
Pacific  Railroad, 
Pittsburgh  and  Connels- 
ville,  (estimated) 


igth  in  feet. 

Time  in  days. 

Average  daily  ad 
vance,  in  feet. 

3,612 

697 

5.18 

4,100 

750 

5.47 

2,250 

675 

3.32 

1,240 

524 

2.37 

700 

210 

3.33 

4,500 


810 


General  average  daily  advance,  in  feet, 
Those  marked  *  being  for  a  double  track. 


5.56 
4.205 


The  following  table  also  gives  the  time  and  cost  of  other 
tunnels  in  different  parts  of  the  world. 


Name  and  location  of  tunnel. 

Material. 

Length 
in  feet. 

Time 
in 
days. 

Daily 
average 
in  feet. 

Section. 

Coat 

Nerthe,  France, 

Hard  limestone 

15,153 

,X26± 

$ 

Riqueral      " 

Chalk 

18,623 

2,139 

8.7 

•2(\ 

x  2e| 

39.89 

Pouilly,        " 

Chalk  &  clay 

10,9282,504 

4.4 

20; 

X20} 

113.96 

Arscherville,  France, 

7,348  1,878 

3.9 

2r>; 

X  26£ 

68.38 

Maurage,            " 

15,752 

2,085 

7.5 

25 

X  25} 

94.43 

Rolleboise 

Chalk 

8,670 

626 

13.9 

25' 

'  X25 

62.98 

Roule, 



5,645 

522 

10.8 

2.-> 

X  25 

62.98 

Lioran, 
Kilsby,  England, 

4,548 
7,233 

2,087 
1,252 

2.2 

5.8 

27' 

X  23| 

56.98 
194.31 

Clay  and  sand 

Belchingly,    " 
Thames  &  Medway,  Eng'd, 

Blue  clay 
Chalk    " 

3,972 
11,880 

626 
939 

6.3 
12.6 

24 
•50 

X  25 
X38| 

102.86 
45.59 

Box,  England, 

Marble,  freestone 

and  marl 

9,680 

1,252 

7.7 

55 

X39 

148.15 

Harecastle,  England, 

Rock  and  sand 

8,778 

939 

9.3 

14 

X  16 

57.05 

Nochistingo,  Mexico, 

Clay  and  marl 

21,659 

287 

75.4 

isf  x  iij 



Blisworth,  England, 

Rock  and  clay 

9,240 

2,191 

4.2 

16j 

X  18 

23.18 

Supperton,         " 

Rock 

12,900 

1,878 

6.9 

15 

X  15 

12.44 

Black  Rock,  W.  S. 

Greywacke  slate 

1,932 





19 

x  m 

77.18 

Blaisy,  France, 

Chalk  and  clay 

13,455 

1,043 

12.9 

26£  X  26| 

136.06 

Edge  Hill,  England, 

Clay  &  freestone 

6,600 





22 

X  16 

30.15 

Littlebourg,       " 



8,607 

590 

14.6 

27£  X  24 

129.61 

Woodhead,       " 

Millstone 

15,840 

1,800 

8.8 

~~ 

ROCKWORK.  121 

The  cost  per  cubic  yard  for  excavating  tunnels  in  some 
places  has  been  as  follows :  — 

Name.  Material.  Cost  per  cubic  yard. 

Blackrock,  U.  S.  hard  greywache  slate,  $6.60 

Lehigh,  U.  S.  very  hard  granite,  4.36 

Schuylkill,  U.  S.  slate,  2.00 

Union,  U.  S.  slate,  2.08^ 

Blue  Ridge,  U.  S.  ,  4.00 

The  Blue  Ridge  tunnel  on  the  Virginia  Central  Railroad 
is  4,280  feet  long,  made  for  a  single  track,  21  X  15  feet. 
Lining  about  four  feet  thick.  Excavation  where  lining  is 
used  is  26  X  23. 

The  Hoosac  tunnel  (Massachusetts)  is  proposed  to  be 
four  and  one  half  miles  long,  23  X  22  feet  section.  To 
have  two  shafts  eight  hundred  and  fifty  and  seven  hundred 
and  fifty  feet  deep,  and  ten  feet  in  diameter. 

Artificial  ventilation  becomes  necessary  in  headings  over 
four  hundred  and  fifty  or  five  hundred  feet  in  length. 

The  cost  of  the  shafts  of  the  Belchingly  tunnel,  (England,) 
ninety-seven  feet  deep,  and  ten  and  one  half  feet  in  diame 
ter,  cut  through  blue  clay,  and  lined,  was  $68.44  per  yard 
down. 

The  shafts  of  the  Blaisy  tunnel  average  five  hundred  feet 
deep,  through  clay  and  chalk  and  loose  earth,  (being  lined,) 
cost  $139.11  per  yard  down. 

The  shafts  of  the  Black  Rock  tunnel,  one  hundred  and 
thirty -nine  feet  deep,  in  hard  slate,  cost  $18.72  per  cubic 
yard. 

11 


CHAPTER    VIII. 

WOODEN  BRIDGES. 


139.  WOODEN  bridging,  owing  to  its  cheapness  and  fit 
ness   for   universal   application,  has    been    and    is    being 
adopted  in  all  parts  of  the  country.     Almost  any  variety  of 
form  may  be  seen  upon  our  railroads,  and  though  less  dura 
ble  than  stone  or  iron,  it  may  with  proper  precaution  be 
made  to  last  a  long  time. 

OF  THE  FOKCES  AT  WORK  IN  BRIDGES. 

140.  There  are  four  distinct  strains  to  which  a  piece  of 
timber  or  a  bar  of  metal  may  be  exposed,  each  of  which 
tends   to   destroy   the  piece  in   a  different  manner.     The 
amount  and  character  of  these  strains,  depend  upon  the  po 
sition  of  the  bar  or  beam,  and  upon  the  direction  of  the 
force. 

A  beam  may  be  pulled  apart  by  stretching,  —  Tension. 
It  may  be  destroyed  by  crushing,  —  Compression. 
It  may  be  broken  transversely,  —  Cross  strain. 
It  may  be  crushed  across  the  grain, —  Detrusion. 


WOODEN  BRIDGES.  123 


TENSION. 

141.  If  one  thousand  pounds  were  hung  from  the  end  of 
a  suspended  timber,  so  that  the  direction  of  the  weight  co 
incides  with  the  axis  of  the  timber,  then  will  the  tension 
upon  the  beam  be  one  thousand  pounds. 

If  the  direction  of  the  force  is  vertical,  and  the  beam  is 
inclined,  then  the  strain  is  increased  by  as  much  as  the  di 
agonal  of  inclination  exceeds  the  vertical ;  for  example,  let 
one  thousand  pounds  be  suspended  from  the  lower  end  of  a 
beam  ten  feet  long,  inclined  at  an  angle  of  45°.  The  diag 
onal  being  ten,  the  vertical  will  be  7.07  feet,  and  the  strain 
is  increased  as  follows :  — 

7.07  to  10  as  1,000  to  1,414  Ibs. 

As  the  angle  of  inclination,  from  the  horizontal,  increases, 
the  strain  from  a  given  load  decreases,  until  the  beam  is 
vertical,  when  a  weight  acts  with  its  least  power. 

COMPRESSION. 

142.  If   a   vertical   post  is   loaded  with   one   thousand 
pounds,  the  compressive  strain  upon  that  post  will  also  be 
one  thousand  pounds.     If  a  post  is  inclined,  the  amount  of 
strain  is  increased,  as  noticed  in  the  case  of  tension,  and  to 
the  same  amount,  that  is,  depending  upon  the  inclination. 

A  piece  of  wood  or  metal  acting  as  a  post,  or  pillar,  must 
not  only  be  able  to  resist  crushing,  but  also  bending  or 
bulging  laterally. 

143.  A  cylinder  of  which  the  length  is  only  seven  or 
eight  times  the  diameter,  wilt  not  bulge  by  any  force  that 
can  be  applied  to  it  longitudinally,  but  will  split.     When 
the  length   exceeds  this,  it  will  be   destroyed  by  a  similar 
movement  to  that  produced  by  a  cross  strain.     When  the 


124  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

length  of  a  cast-iron  pillar  is  thirty  diameters,  the  fracture 
is  produced  by  bending  alone  ;  when  less,  partly  by  bend 
ing  and  partly  by  fracture.  When  the  column  is  cast  hol 
low,  and  enlarged  towards  the  middle,  the  strength  is  in 
creased  in  a  very  great  ratio. 

144.  The  formula  for  finding  the  weight  which  any  beam 
acting  as  a  post,  will  support  before  bending,  is,  according 
to  Barlow,  who  considers  the  weight  as  varying  inversely 
as  the  length,  as  follows  :  — 


and  the  value  of  W  is 


and  the  weight  being  given,  and  the  sectional  dimensions 
assumed,  we  have 


tt  =     Wl? 

and 

,,_     WL2 

i  j 


Where  W  represents  the  weight  in  pounds, 
L  "         "     length  in  feet, 

E  "a  constant, 

d  "      the  depth  in  inches, 

b  "         "   breadth  in  inches. 


CROSS    STRAIN. 

145.  The  amount  of  strain  caused  by  any  weight  ap 
plied  in  a  transverse  direction,  to  a  beam  supported  at  both 
ends,  is  as  the  breadth,  as  the  length  inversely,  and  as  the 


WOODEN   BRIDGES.  125 

square  of  the  depth.  Whatever  depression  takes  place, 
tends  to  shorten  the  upper,  and  to  extend  the  under-side ; 
whence  the  fibres  of  the  top  part  suffer  compression,  and 
those  of  the  bottom  extension.  The  amounts  of  compres 
sion  and  extension  must  of  course  be  equal,  and  therefore 
if  any  material  resists  these  two  strains  in  a  different  de 
gree,  the  number  of  fibres  opposing  each  will  also  be  dif 
ferent. 

The  top  being  compressed,  while  the  bottom  is  extended, 
of  course  at  some  point  within  the  beam  there  exists  a  line 
which  suffers  neither  compression  nor  extension.  The 
position  of  this  line  (the  neutral  axis)  depends  upon  the 
relative  power  of  the  material  to  oppose  the  strains,  upon 
its  form  and  upon  its  position.  Thus  if  wood  resists  two 
thousand  pounds  per  square  inch  of  extension,  and  one 
thousand  pounds  of  compression,  the  axis  will  be  twice  as  far 
from  the  top  as  from  the  bottom. 

In  some  materials  the  neutral  axis  changes  its  place 
while  the  bar  is  at  work  ;  thus  wrought  iron,  after  being  a 
little  compressed,  will  bear  a  great  deal  more  compression 
than  when  in  its  original  state ;  also  the  lower  fibres,  after 
being  extended,  will  resist  less  than  at  first ;  the  effect  of 
which  two  actions  is  to  move  the  neutral  axis  up. 

146.  The  following  table  shows  the  relative  resisting 
powers  of  wood,  wrought  and  cast-iron;  with  the  corre 
sponding  positions  of  the  axis,  with  sufficient  accuracy  for 
practice. 

n/Tof^o!  Resistance  to        Resistance  to    -n  <.•  Distance  of  axis  from  top,  in 

extension.  compression.    *  fractions  of  the  depth. 

Wrought  iron,         90  66  f  §  •£&  or  0.58 

Cast-iron,  20  140          ffa  -^  or  0.13 

Wood,  2  1  £  §    or  0.66 

Thus  in  beams  subjected  to  a  cross  strain,  as  well  as  to  a 

11* 


126  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

direct  extensive  or  compressive  one,  the  resistance  is  effected 
by  the  incompressibility  and  inextensibility  of  the  material. 
147.    The  formula  for  dimensioning  any  beam  to  support 
a  given  weight  transversely  is 


Where  S  represents  the  ultimate  strength  in  Ibs. 
b  "  "     breadth  in  inches, 

d          «  «     depth  « 

e  "  "     length          " 

DETRUSION. 

148.  Detrusion,  or  crushing  across  a  fixed  point,  is  such 
as  occurs  wherever  a  brace  abuts  against  a  chord,  or  where 
a  bridge  bears  upon  a  bolster  or  wall  plate  ;  also  the  shear 
ing  of  bolts,  pins,  and  rivets. 

GENERAL    RESISTANCE    OF    MATERIALS. 

149.  The  resistance  to  extension,  to  compression,  (as  re 
gards  simple  crushing,)  and  to  detrusion,  is  as  the  area  of 
cross  section  ;   i.  e.,  if  we  double  the  area,  we  double  the 
strength.     The  resistance  to  a  cross  strain  is  as  the  breadth, 
as  the  length  inversely,  and  as  the  square  of  the  depth  ;  i.  e. 
if  we  double  the  breadth  we  double  the  strength  ;   if  we 
double  the  length,  we  divide  the  strength  by  two  ;    and  if 
we  double  the  depth,  we  multiply  the  strength  by  four. 

ACTUAL   STRENGTH  OF  MATERIALS. 

150.  Any  material  will  bear  a  much  larger  load  for  a 
short  time  than  for  a  long  one.     The  weight  that  does  not 
so  injure  materials  as  to  render  them  unsafe,  is  from  one 


WOODEN  BRIDGES.  127 

third  to  one  fourth  only  of  the  ultimate  strength.  Through 
out  the  present  work  one  fourth  will  be  the  most  that  will 
in  any  ease  be  used. 

WROUGHT    IRON. 

151.    Extension. 

Ibs.  per  square  inch. 

Mean  of  17  experiments  by  Barlow  (p.  270)  62,720 

Weisbach's  Mechanics  (Vol.  ii.,  p.  71)  60,500 

Overman's  Mechanics,  (p.  408,  409)  61,333 

Brown,  Rennie,  and  Telford,  (mean)  67,200 

The  mean  62,451 


Reducing  by  4  for  safety  15,613 

Or  in  round  numbers  15,000  Ibs.  per  square  inch,  is  the 
resistance  of  wrought  iron  to  extension,  to  be  used  in 
practice. 

152.  Compression.  —  Great  discrepancies  appear  among 
writers  on  the  strength  of  materials,  as  to  the  compressive 
strength  of  wrought  iron.  Though  all  estimate  the  resist 
ance  to  compression,  as  great  as  to  extension,  yet  no  one 
in  summing  up  the  general  result  of  experiment,  places  the 
former  at  more  than  from  50  to  75  per  cent,  of  the  latter. 
William  Fairbairn  gives,  as  the  relative  resistances  to  ex 
tension  and  compression  in  bars  applied  as  girders,  2  to  1. 

We  have  by  Weisbach  56,000 

"  «      Rondelet  70,000 

"  «  Hodgekinson  65,000 

The  mean  63,667 

Reducing  by  4  15,917 

In  round  numbers  16,000  Ibs.  per  square  inch. 

As  far  as   practice  is  any  guide,  from  8,000  to  12,000 


128 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


pounds  per  inch  is  the  most  to  be  used.  The  ratio  of  90  to 
66,  seems  to  express  very  nearly  the  action  as  in  the  most 
reliable  structures;  which  will,  therefore,  be  adopted,  or 
12,000  pounds  per  square  inch  nearly.  The  resistance  to 
compression  is  very  much  greater  after  wrought  iron  has 
been  somewhat  compressed. 

CAST-IRON. 

153.  Extension.  —  This  material  is  seldom  used  to  resist 
a  tensile  force.     That  the  tables  may  be  complete,  however, 
the  following  is  given  :  — 

By  Weisbach  20,000  pounds. 

By  Barlow  18,233 

By  Overman  20,000 

By  Rennie  18,000 

By  Hodgekinson  16,577 

By  the  British  Iron  Commission  15,711 

The  mean  18,087        " 

Reducing  by  4  4,522        " 

In  round  numbers  4,500        " 

154.  Compression. 

By  Weisbach  109,800  pounds. 

By  Hodgekinson  107,520  " 

By  Iron  Commission  100,000  « 

Stirling's  toughened  130,000  " 

Mean  of  Common                              .  105,773  " 

Mean  of  Stirling's  130,000  « 

Reducing  by  4  for  safety  (Common)  26,443  " 

Reducing  by  4  for  safety  (Stirling's)    32,500  " 

•  In  round  numbers  (Common)  25,000  " 

In  round  numbers  (Stirling's)  30,000  " 


155.   Following  are  given  the  condensed  results  of  the 


WOODEN  BRIDGES. 


129 


preceding  figures,  which  may  be  relied  upon  as  giving  per 
fectly  safe  dimensions  in  practice. 


Wrought  Iron. 

15,000 
12,000 


Cast-iron. 
4,500 

25,000 


Tensile  strength, 
Compressive  strength. 


For  additional  remarks  on  iron,  see  chap.  IX. 


156.  Nature  and  Strength  of  American  Woods. 


xr          f  *v*          A    Weight  per  Resistance  to    Resistance  to    voii-m  nf  <? 
Name  of  the  wood.    cubfc  fo£t.     Extension.      Compression.     Value  of  S' 


Elasticity. 


vv  uue  jrintJ 

^0 

LLfJ\J\J 

u,vw 

J.,^Z/«/ 

Yellow  Pine 

31 

12,000 

6,000 

1,185 

Pitch  Pine 

46 

12,000 

6,000 

1,727 

4,900 

Red  Pine 

35 

12,000 

6,000 

1,527 

7,359 

Virginia  Pine 

37 

12,000 

6,000 

1,456 



Spruce 

48 

12,000 

6,000 

1,036 

Larch 

33 

12,000 

6,000 

907 

2,465 

Tamarack 

26 

12,000 

6,000 

907 



White  Cedar 

22 

8,000 

4,000 

766 



Canada  Balsam 

34 

12,000 

6,000 

1,123 



White  Oak 

48 

15,000 

7,500 

1,743 

8,595 

Red  Oak 

41 

15,000 

7,600 

1,687 

Live  Oak 

72 

15,000 

7,200 

1,862 

White  Beech 

44 

18,000 

9,100 

1,380 

5,417 

Red  Beech 

48 

18,000 

9,000 

1,739 



Birch 

44 

15,000 

7,000 

1,928 



Black  Birch 

41 

15,000 

7,200 

2,061 



Yellow  Birch 

36 

15,000 

7,200 

1,335 

Ash 

38 

16,000 

8,100 

1,795 

6,581 

Black  Ash 

35 

16,000 

8,000 

861 

Swamp  Ash 

57 

16,000 

8,000 

1,165 



Hickory 

51 

15,000 

7,200 

2,129 

Butternut 

54 

15,000 

7,600 

1,465 

Sun  Wood 

54 

16,000 

8,100 

1,800 



Rock  Elm 

45 

16,000 

8,011 

1,970 

2,799 

130'  HANDBOOK   OF  RAILROAD   CONSTRUCTION 

The  mean  tensile  strength  of  wood  is  14,080  Ibs. 
Reducing  by  4  for  safety  3,520  " 

Reducing  for  want  of  seasoning  2,000  " 

The  reduced  mean  compressive  strength  1,000  " 

Reduced  resistance  to  detrusion  150  " 

Ratio  of  tensile  to  compressive  strength  2  to  1. 
Mean   value  of  S  in  formula  (  WL2=±  Sbd2)  for  the 

woods  most  used  in  practice  1,250. 

157.  The  lateral  adhesion  of  fir  was  found,  by  Barlow, 
to  be  six  hundred  pounds  per  square  inch.     (Lateral  adhe 
sion  is  the  resistance  which  the  fibres  offer  to  sliding  past 
each  other  in  the  direction  of  the  grain ;  as,  in  pulling  off 
the  top  of  a  post  where  it  is  halved  on  to  the  chord.) 

158.  As  regards  the  nature  of  timber,  seasoning,  time  of 
cutting,  etc.,  although  these  are  important  items,  still,  gen 
erally,  commercial  considerations  outbalance  all  else.     The 
most   complete  treatise  on  the  nature  of  woods,   is   "  Du 
Hamel,  Sexploitation   des   bois ; "  from   which  it  appears 
that   the   best   oaks,  elms,  and   other   large  trees,  are  the 
product  of  good  lands,  rather  dry  than  moist.     They  have 
a  fine,  clear  bark,  the  sap  is  thinner  in  proportion  to  the 
diameter  of  the  trunk,  the  layers  are  less  thick,  but  more 
adherent  the  one  to  another ;  and  more  uniform  than  those 
of  trees  growing  on  moist  places.     The  grain  of  the  latter 
may  look  very  fine  and  compact,  but  microscopic  examina 
tion  shows  the  pores  to  be  full  of  gluten. 

The  density  of  the  same  species  of  timber,  in  the  same 
climate,  but  on  different  soils,  will  vary  as  7  to  5 ;  and  the 
strength,  both  before  and  after  seasoning,  as  5  to  4. 

In  trees  not  beyond  their  prime,  the  density  of  the  butt 
is  to  that  of  the  top,  as  4  to  3 ;  and  of  centre  to  circum 
ference,  as  7  to  5.  After  maturity,  the  reverse  occurs  in 
both  cases. 


WOODEN  BRIDGES.  131 

Oak,  in  seasoning,  loses  from  1  to  J  of  its  weight  ;  but 
its  strength  is  increased  from  30  to  40  per  cent. 

^ 

GENERAL  TABLE  OP  THE  NATURE  OF  MATERIALS. 

159.  The  tensile  strength  of  wrought  iron  assumed  as 
1,000. 

Material.  Tension.    ^          <£-  Sun,.      ^ff  ^n? 

Cast-iron  300     1,666       31.68       1,997.68     450  4.4 

Wrought  Iron  1,000       733       55.40       1,788.40     480  3.7 

Wood  143         66        5.60         204.60       30  6.8 

The  advantage  possessed  by  iron  over  wood,  is  in  dura 
bility  only.  The  above  figures  show  how  much  more  of  the 
strength  of  the  material  is  consumed  by  its  own  weight  in 
iron  than  in  wood.  In  actual  practice,  however,  the  method 
of  making  joints  and  other  details  often  render  iron  the 
lightest  material. 

KULES  FOR  PRACTICE. 

TENSION. 

160.  The  tensile  strength  of  any  material,  is  expressed 
by  the  formula 


Where  ^represents  the  whole  strength, 

S        "  "    strength  per  square  inch, 

a         "  "    area  of  section  in  inches. 

whence  the  necessary  area  of  section  of  any  material   to 
resist  a  tensile  strain,  is  found  by  the  following  rules  :  — 


132  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Wrought  Iron 

W 


~~  15,000 ' 

Cast- Iron 

W 

~~  4,500 ' 

Wood 

W 

""2,000* 

COMPRESSION. 

161.    Wrought  Iron 

W 
a 


12,000' 

Cast-Iron 

W 


25,000 ' 

Wood 

W 

a~~i£0d' 


CROSS    STRAIN. 


162.    The  power  of  any  material  to  resist  a  cross  strain, 
is  shown  by  the  formula 


Where  W  represents  the  breaking  weight  in  pounds, 

s  "  "   constant  in  the  table  of  woods, 

b  "  "   breadth  in  inches, 

d          "  "   depth  in  inches, 

and  L         "  "  length  in  inches, 


WOODEN  BRIDGES.  133 

and  to  reduce  the  load  to  one  fourth  of  the  breaking  weight 


and  finally,  by  substituting  for  4  s,  4  X  1,250,  (1,250  of  the 
table  of  woods,)  we  have 

w_5000b_d2 

Also,  knowing  the  weight  to  be  supported,  and  requiring 
the  dimensions,  we  take  out  the  values  of  d  and  &,  and 
have 


=*e  breadth- 

As  an  example  of  the  use  of  the  formula,  take  the  fol 
lowing  :  — 

Let  the  span,  or  length,  be  20  feet, 
The  breadth  12  inches,  and  depth  18, 

required  the  load. 

The  formula 

_     5000  bdz 

~ur 

becomes 


Again,  the  weight  to  be  supported  being  15,000  Ibs., 
length  30  feet,  breadth  16  inches,  the  formula  for  the  depth/ 
becomes 

/  15000  X  1440 
=  V      5000  X  16      =  V270  =  16  inches, 

also, 

15000X1440        21600000 
b==     5000X256"=  1280000  =16 
12 


134 


HANDBOOK  OF  RAILROAD   CONSTRUCTION. 


CAST-IRON. 


163.    The  formula,  expressive  of  the  strength  of  a  cast- 
iron  beam,  is 


from  which  we  have 

*=5=tbe  breadth, 


and  ^ 


he  depth. 


WROUGHT   IRON. 


164. 

whence 


WL 
~*~  the  breadth» 


the  depth. 


Length     .         .         • 

Height 

Area  of  top  flange    . 

Area  of  lower  flange 


165.  Mr.  Hodgekinson  found, 
that  by  arranging  the  material 
in  a  cast-iron  beam,  as  in  fig. 
60,  that  the  resistance  per  unit 
of  section  was  increased  over 
that  of  a  simple  rectangular 
beam,  in  the  ratio  of  40  to  23. 
He  makes  the  general  propor 
tion  of  such  girders  as  fol 
lows  :  — 

16 

.       1 
1.0 
6.1 


WOODEN  BRIDGES.  135 

In  this  consummate  disposition  of  material,  the  areas  of 
top  and  bottom  flanges  are  made  inversely  proportional  to 
the  power  of  cast-iron  to  resist  compression  and  extension. 

166.  Mr.  Fairbairn  found,  that  in  wrought  iron  flanged 
girders,  (under  which  come  the  various  rails,  chap.  XIII.,) 
the  top  web  should  contain  double  the  area  of  the  lower 
one.    This  agrees  with  the  conclusion  adopted  on  page  129, 
as  wrought  iron  resists  more  extension  than  compression. 

167.  In  cast-iron  girders,  on  no  account  should  there  be 
introduced  webs,  or  openings  of  any  kind,  either  from  eco 
nomic  or  ornamental  motives  ;  as  the  uniformity  of  cool 
ing  is  thereby  very  much  opposed. 

168.  Mr.  Hodgekinson  gives,  as  the  result  of  his  experi 
ments,  the  following  formula  for  dimensioning  the  cast-iron 
girder  above  referred  to. 


Where  If  is  the  breaking  weight  in  tons, 
a  the  area  of  the  bottom  flange, 
d  the  depth  of  the  girder  in  inches, 
L  the  lenth  in  inches. 


As  it  is  not  considered  safe  to  load  a  cast-iron  beam  with 
more  than  one  sixth  of  the  breaking  load,  the  formula  may 
be  expressed  as  follows  :  — 

Wad 

:~6zr> 

for   the   weight  in   tons  which  may  be  safely  borne,  and 
transforming 


for  the  area  of  the  lower  flange. 


136  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Example.  —  Required  the  dimensions  of  a  cast-iron  beam, 
of  Mr.  Hodgekinson's  form,  for  a  span  of  thirty  feet,  to  sup 
port  a  load  of  ten  tons  at  the  centre. 

_6X10X30X12_21,600 
~~ 


and  the  area  of  the  top  flange  will  be 

36_ 

whence  the  following  dimensions  :  — 

Length    .     '    .         .         .         .  30  feet, 

Depth 23  inches, 

Lower  flange  .         .         .         .  36  square  inches, 
Upper  flange       ....       6      "  " 

OF   POSTS. 

169.  A  post  may  be  very  well  able  to  resist  the  com- 
pressive  strain  thrown  upon  it  by  any  load,  but  may  bulge, 
or  bend,  laterally. 

The  formula  by  which  beams  are  dimensioned  for  this 
requirement,  changes  with  the  material,  and  with  the  form 
of  section.  For  rectangular  posts  of  wood,  we  have  the 
formula  below. 

2240  bds 


W= 


L2 


Where  W  represents  the  weight  in  Ibs.,  which  may  be  safely  borne, 
b         "  "     breadth  in  inches, 

d         "  "     depth  in  inches, 

and  L        "  "     length  in  feet. 

170.    The  value  of  the  formula  for  the  strength  of  cast- 
iron  posts,  seems  to  depend  more  upon  the  authority  con- 


WOODEN  BRIDGES.  137 

suited  than  upon  the  nature  of  iron.  For  example,  assume 
the  length  of  a  post  as  twenty  feet,  and  the  diameter  as  ten 
inches ;  the  load  which  may  be  safely  borne  is,  according 
to  six  different  authorities,  as  follows :  — 

A  4,000,000 

B  181,100 

C  370,000 

D  940,000 

E  307,242 

F  300,000 

and  assuming  the  length  as  ten  feet,  and  diameter  as  ten 
inches,  we  have 

A  8,007,500 

B  204,500 

C  1,442,500 

D  3,640,000 

E  1,170,000 

F  600,000 

showing  not  only  a  great  difference  in  the  unit  resistance 
taken,  but  also  in  the  effect  of  the  ratio  between  the  length 
and  diameter. 

Such  being  the  discrepancy,  there  will  be  given  no  for 
mula  ;  but  in  place  of  such,  the  table  following,  which  is 
calculated  from  the  rules  least  opposed  to  experimental 
evidence. 

12* 


O 
OJ 


C5  00 
TO  TO 


§8 


^iOC^COO^ 


o  o  o  o 


>-i  f-i  (N  W  CO  CO 


§ 


GO 


•-<  (N  co  n  o 


00 


CO 


CQ 


Hw      Hop  <«!»•  fruoH" 


525 


a 


r-T}ii— icJitO 


00 


a 


WOODEN  BRIDGES.  139 


OF  THE  TRUSS. 

171.  The  most  simple  bridge  that  could  be  built,  consists 
of  a  single  piece  of  timber  placed  across  the  opening  to  be 
spanned.  This  form  is  applicable  to  spans  under  twenty 
feet.  The  proper  dimensions  are  found  by  the  formula  — 


l±wL 
d=\  5000ft  = 


Example.  —  The  depth  of  a  beam  of  twenty  feet  span, 
and  twelve  inches  wide,  to  support  a  load  of  twenty  thou-' 
sand  two  hundred  and  fifty  Ibs.  is 


5000  X  12 

A  beam  12  X  18?  and  of  20  feet  span,  will  therefore  bear 
safely  a  load  of  20,250  Ibs.,  applied  at  the  centre. 

In  this  manner  is  formed  the  following  table,  giving  the 
scantling  of  sticks  for  railroad  stringer  bridges,  of  twenty 
feet  span  and  under. 

Span.  Breadth,  Depth.. 

5  12  12 

10  12  13 

12  12  15 

15  12  18 

18  12  20 

20  12  21  inches. 

The  first  scantlings  exceed  the  requirement  of  the  rule,  but 
are  none  too  large  to  resist  the  shocks  to  which  such  sticks 
are  exposed. 

Cross-ties  of  plank,  2  or  3  by  6  or  8  inches,  and  plank 
braces  underneath,  (as  shown  in  the  fig.  at  the  end  of  chap 
ter  VIII.,)  should  be  bolted  to  the  main  timbers ;  the  same 


140  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

bolt  passing  through  the  tie  beam  and  plank.  The  longi 
tudinal  pieces  should  be  firmly  notched  and  bolted  to  the 
wall-plates,  and  these  latter  either  built  in  or  scribed  on  to 
the  masonry. 

172.    For  a  span  of  from  20  to  50  feet,  we  may  use  the 

combination  shown  in  fig.  61.     The  piece  A  B,  must  be  so 

rig.  ei.  strong  as  not  to 

yield  between  A 
and  I),  or  D  and 
B.  The  pieces 
C  E,  must  be  stiff 
enough  to  resist 
the  load  coming 
upon  them  which 
is  as  follows.  A  locomotive  engine  of  the  heaviest  class  will 
not  exceed  fifty  tons  weight,  each  pair  of  driving  wheels  will 
support  ten  tons,  and  on  each  side  five  tons,  2240  X  5, 11,200 
Ibs. ;  or  to  allow  for  shocks  and  extra  strains,  15,000  Ibs. 
Each  brace,  then,  must  support  seven  thousand  five  hundred 
pounds,  which  for  compression  simply  would  require  only 
seven  and  one  half  square  inches  of  sectional  area ;  but  the 
brace  being  inclined,  the  strain  is  increased  as  follows :  — 

A  E  to  E  C  as  7,500  to  X. 

And  A  E  being  ten  feet,  and  A  D  fifteen  feet,  E  C  becomes 
eighteen  feet,  whence 

10  to  18  as  7,500  to  13,500  Ibs. ; 

which  would  require  only  thirteen  and  one  half  inches  for 
compression,  or  a  piece  4  X  3i.  But  is  this  enough  for 
flexure  ? 

On  page  124  the  load  which  may  be  safely  borne,  by  a 
rectangular  post  of  wood,  is  shown  by  the  formula 


WOODEN  BRIDGES.  141 

2240  bd3 

-~z^~- 

Substituting  for  b  and  d,  the  dimensions  4x4,  we  have 

~W 
which  is  evidently  too  small. 

Placing  6  X  7,  for  b  X  d,  we  have 

IF^2240X6X73^U  227  ^ 

exceeding  by  a  small  amount  the  requirement. 

173.  It  is  evidently  immaterial  whether  we  support  the 
the  point  D  upon  C,  or  suspend  it  as  in  fig.  62,  provided 
we  prevent  any  Fig.  62. 

motion  in  the 
feet  of  the  in 
clines  A  c  B  c. 
Abutting  them 
against  A  B, 
throws  a  ten 
sion  against  A  B,  found  as  follows :  — 

Representing  by  c 
D.  the  applied  weight, 
draw  D  E  parallel  to 
c  B  ;  also  E/  parallel 
to  AB;  E/  is  the 
tension.  The  graphic  construction  gives  results  near  enough 
for  practice.  Rigorously  we  have 

A  c  D,  similar  to  E  cf; 
also, 

A  c,  to  E  c,  as  A  D,  to  E/; 
and 


When  a  d  and  c  d  are  differently  inclined,  proceed  as  fol 
lows.     See  fig.  102,"  p.  200. 


142 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


Let  d  b  represent  the  weight ;  e  h  shows  the  tension.  The 
triangles  acd,  and  a  b  e,  are  similar ;  as  also  e  b  h  and  d  b  c ; 
whence 

a  b,  c  d  cb,be 

,  and  e  h  =  — ^ —  =  tension. 


ac 


dc 


In  practice  place  w  for  b  d ;  i.  e.  the  actual  weight. 

In  this  plan,  if  the  chord  is  able  to  resist  the  cross  strain 
between  A  and  D,  it  will  also  resist  the  tension.  This  cross 
strain  is  found  by  the  formula  already  given  and  illus 
trated. 

174.  From  what  precedes,  we  have  the  following  dimen 
sions  for  bridges  such  as  are  shown  in  figs.  61  and  62. 
The  details  of  62,  at/  and  c,  and  at  E,  61,  are  shown  in  figs. 
62  A,  62  B,  and  61  C. 

Fig.  62  A. 

I^^^H^^HHHl  -rt  •  „      /tA  T% 

Kg.  61  C. 


Span. 

Rise. 

AB. 

CE. 

Rod6. 

20 

8 

12X12 

(5X    8)  —  2 

1^  inches. 

25 

10 

12X15 

(5X    9)  —  2 

it   « 

30 

12 

12  X  18 

(5X10)  —  2 

H    " 

35 

13  ' 

12X20 

(5X  10)  —  2 

IF     " 

40 

14 

14X21 

(5X12)  —  2 

IS     "  ' 

45 

15 

14  X  22 

(6X12)  —  2 

If     " 

50 

16 

14X24 

(6X12)  —  2 

If     " 

The  braces,  (column  4,)  being  in  pairs  and  blocked  together. 
In  span  exceeding  twenty-five  feet,  the  braces  df,  and  the 


WOODEN  BRIDGES.  143 

rods  fg,  should  never  be  omitted.     The  size  of  the  rod  gf, 
is  found  by  considering  A,  d,/,  as  a  small  bridge. 

175.  In  all  light  bridges,  like  the  one  under  consideration, 
all  parts  should  be  fastened  by  bolts,  to  prevent  springing 
by  reaction.     A  bridge  with  but  little  inertia,  or  dead  weight, 
tends  to  jump  up  when  the  engine  has   passed   over  it. 
Fastening1  takes  the  place  of  weight  in  a  large  span. 

As  soon  as  the  rise  admits,  the  points  C,  on  each  side  of 
the  bridge,  should  be  connected  to  resist  lateral  motion. 
When  the  height  is  not  enough  for  this,  the  same  points 
may  be  joined  to  a  floor  beam  extended  out  beyond  the 
truss. 

Though  the  dimensions  are  given  for  this  plan  up  to  fifty 
feet  span,  it  is  very  seldom  advisable  to  go  beyond  twenty- 
five  or  thirty  feet ;  as  frames  consisting  of  a  few  long  tim 
bers  are  not  so  rigid,  and  free  from  vibration,  as  those  made 
of  a  greater  number  of  short  pieces. 

176.  In  extending  this  system  one  hundred  or  two  hun 
dred  feet,  we  see  at  once  that  the  pieces  A  c,  B  c,  would 
become  very  long  and  would  need  to  be  made  large  and 
heavy.     We  should  always  so  proportion  any  beam  in  a 
bridge  that  it  is  at  once  able  to  resist  all  of  the  several 
strains  to  which  it  may  be  exposed,  without  being  unneces 
sarily  large. 

As  to  compression,  the  above  system  might  be  extended 
to  almost  any  amount;  but  the  braces  would  yield  by 
flexure. 

Instead  of  producing  the  braces  A  c,  A'  c',  fig.  64.  to  their 
intersection,  we  stop  at  c  and  c',  insert  c  cf ;  to  prevent  the 
approach  of  these  points,  suspend  the  points  B  and  B'  from 
c  and  c',  and  commence  again  with  the  braces  B  D,  B'  D ; 
and  so  on  as  far  as  necessary. 

To  prevent  the  backward  motion  of  the  points  B,  and  B', 


144 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


either  the  chord  A  A',  or  the  counter-braces  w,  w,  are  nec 
essary. 

Fig.  64. 


The  pieces  A  c  A'  c'  must  support  all  of  the  load,  including 
the  weight  of  the  bridge,  lying  within  the  rectangle  B  c  B'  c'. 
The  next  set  of  braces  must  sustain  that  part  of  the  load 
only  which  comes  over  the  centre  of  the  bridge.  Thus  the 
braces  should  decrease  in  size  as  the  centre  is  approached. 
The  rods  c  B,  c'  B',  must  resist  a  tension  equal  in  amount 
to  the  pressure  on  the  braces,  only  being  vertical  they  do 
not  need  the  increase  given  to  the  braces  on  account  of  their 
inclination. 

177.  There  is  another  method  of  stiffening  a  beam,  as 
shown  in  figs.  65  and  66,  by  trussing  rods,  and  a  post.  The 
dimensions  being  the  same,  the  forces  in  both  cases  will  be 
equal.  The  second,  fig.  66,  leaves  the  passage  beneath  the 
bridge  clear. 

The  tension  on  the 
rods  Ac,  Be,  fig.  66, 
tends  to  draw  the  points 
A  and  B  together,  an 
effort  which  is  resisted 
by  the  top  chord  A  B. 
In  extending  this  system,  as  in  art.  176,  the  rods  become 


rig.  65. 


WOODEN   BRIDGES.  145 

either  very  long,  or 
very  large,  from  the 
small  angle  of  in 
clination;  evils 
which  are  reme 
died  as  before,  by 
supporting  the  post 
cB,  fig.  64,  from 
the  foot  of  the  first  rod,  fig.  64,  and  commencing  again 
from  c. 

To  prevent  the  motion  of  the  triangle  c  B  G,  fig.  64, 
about  the  angle  B,  we  must  introduce  either  the  upper 
chord  c  c',  or  the  counter  rod  c  A.  If  the  lower  chord  is 
omitted  the  rod  D  B  must  be  of  the  same  size  as  E  B.  In 
this  truss,  either  the  top  or  the  lower  chord  simply  may 
theoretically  be  omitted,  due  allowance  being  made  in  the 
size  of  the  rods.  In  practice  it  is  never  advisable  to  omit 
either,  as  both  are  required  for  lateral  bracing,  and  for  sup 
port  of  the  road-way. 

Having  said  thus  much  of  the  general  ideas  that  apply 
to  all  bridges,  let  us  now  look  at  some  of  the  plans  most  in 
use ;  and  to  become  familiar  with  the  subject,  work  out  the 
dimensions  of  an  example  of  each  kind. 

178.  As  rods,  nuts,  and  washers  are  used  in  all  bridges, 
the  following  table  may  not  be  out  of  place :  — 

Column  1  gives  the  diameter  of  rod. 

"       2  strength  at  15,000  Ibs.  per  square  inch. 
"       3  the  weight  per  lineal  foot. 
"       4  side  of  the  square  nut. 
"       5  the  thickness  of  the  same. 
"   .    6  the  dimensions  of  washers. 
"       7  the  thickness  of  washers. 
"       8  breadth  (side  to  side)  six-sided  nut. 
"       9  breadth  (across  angles)  six-sided  nut. 
13 


146 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


Column  10  thickness  of  six-sided  nut. 

"       11  number  of  screw  threads  per  inch. 
"       12  gives  the  diameter  of  rod. 


I 

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WOODEN  BRIDGES.  147 

179.    Let  us  now  assume  the  following  data :  — 

Span       .        .        *    "  '  '.  •'     .       ".        200  feet, 
Rise  (centre  to  centre  of  chords)  .     25     " 

Width    ......  20     « 

Length  of  panel  .         .         .         .     15     " 

Weight  (bridge  and  load)  per  lineal  ft.  4,000  Ibs. 

Fig.  67. 
HOWE'S    BRIDGE. 

Fig.  67. 

Lower  Chords.  —  The  ten 
sion,  at  the  centre  of  the  lower 
chord,  is  found  by  dividing'  the 
product  of  the  weight  of  the 
whole  bridge  and  load  by  the 
span,  by  eight  times  the  height, 
or 

T_  WX  S 
8h     ' 

which  becomes,  with  the  above 
data, 

800000  X  200 
r=-  -2-0£-  -  =  800,000  Ibs. 

Here  the  tension  and  the 
total  weight  are  equal,  a  result 
which  can  occur  only  when  the 
rise  is  one  eighth  of  the  span. 
This  is  the  best  ratio  between 
these  dimensions,  as  then  the 
horizontal  and  vertical  forces 
are  equal. 

As  to  the  proportion  of  the 
panel,  (or  the  rectangle  in 
closed  by  the  chords  and  any 
two  adjacent  posts,)  the  ratio 
of  base  to  height  should  be 
such  as  to  make  the  inclina- 


148  HANDBOOK   OP  RAILROAD  CONSTRUCTION. 

tion  of  diagonal  about  50°  from  the  horizontal;  if  much 
less,  the  timbers  become  large  and  heavy ;  and  if  more,  the 
number  of  pieces  is  unnecessarily  increased. 

The  braces  at  the  end  of  a  long  span,  may  be  nearer  to 
the  vertical  than  those  near  the  centre,  as  they  have  more 
work  to  do.  If  the  end  panel  be  made  twice  as  high  as 
long,  and  the  centre  panel  square,  the  intermediates  vary 
ing  as  their  distance  from  the  end,  a  good  architectural 
effect  is  produced. 

To  determine  the  size  of  the  lower  chords,  to  resist  the 
above  800,000  pounds  of  tension,  proceed  as  follows :  Each 
side  truss  will  support  one  half  of  the  whole  load,  or 
400,000  pounds ;  which,  at  2,000  pounds  per  inch,  will 
require  200  square  inches  of  section.  Four  sticks  of  8  X  12 
inches,  give  an  area  of  384  square  inches,  which  must  be 
reduced  as  follows :  Deduct  72  square  inches  for  the  area 
cut  out  by  the  splicing  blocks,  40  inches  for  the  bolts  con- 
neeting  the  pieces,  28  inches  for  inserting  the  foot  blocks, 
and  10  inches  for  inserting  the  washer,  and  we  have  remain 
ing  234  square  inches ;  which  exceeds  by  a  little  the  exact 
demand.  This  excess  (about  one  seventh)  is  a  necessary 
allowance  for  accidental  strain,  to  which  all  bridges  are  sub 
jected. 

The  splices  used  in  bridge  framing  are  shown  in  fig.  67  A 

Fig.  67  A. 


and  fig.  67  B.     For  the  first,  the   depth  of  insertion   and 
length  of  the   block   depend   upon   the   tension  upon  the 


WOODEN   BRIDGES. 


149 


chord.  The  follow 
ing  dimensions  have 
been  much  used 
and  are  perfectly  re 
liable:— 


Span  of  Bridge. 
Feet. 

50 
100 
150 
200 


Fig.  67  B. 


AC 

Feet. 

1.00 
1.25 
1.75 

2.00 


BC 
Irches 

14 

2 

2i 
3 


CD 

Feet. 

1.50 
2.00 
2.25 
2.75 


There  is  no  need  of  cutting  more  than  one  notch,  as  in  the 
figure ;  the  resistance  of  the  triangles  is  thereby  lessened, 
and  the  work  increased. 

In  fig.  67  B,  the  rods  must  of  course  be  able  to  resist  the 
tension  upon  the  one  piece  which  is  cut. 

Upper  Chord. — The  upper  chords  of  a  bridge  suffer  com 
pression,  to  the  same  amount  numerically,  as  the  tension 
on  the  lower  chord ;  as  whatever  tension  is  thrown  by  any 
brace  upon  the  lower  chord,  reacts  as  just  so  much  com 
pression  upon  the  upper.  In  the  case  at  hand,  800,000  Ibs. 
in  all,  or  400,000  on  each  chord. 

The  resistance  to  compression  being  one  thousand 
pounds  per  inch,  renders  necessary  four  hundred  inches  of 
section  to  each  chord ;  four  pieces  8  X  12  give  in  all  three 
hundred  and  eighty-four  inches  of  section,  which  requires 
no  reduction,  as  the  whole  chord  pressing  together  and 
being  properly  framed  is  not  weakened  by  splicing.  The 
splicing  blocks  in  the  upper  are  merely  plain  pieces,  inserted 
one  half  inch,  the  only  duty  being  to  keep  the  sticks  at  the 
proper  horizontal  distance. 

The  spaces  between  the  pieces  should  be  large  enough  to 

13* 


150  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

allow  the  rods  to  pass  without  cutting  the  chords  ;  (two 
inches  answers  every  purpose).  The  bolts  for  splicing, 
have  no  very  great  strain  to  bear.  In  small  spans  from  £ 
to  f  ,  and  in  large  bridges  from  f  to  an  inch  is  enough. 

The  object  in  framing  a  built  beam  for  a  bridge  chord,  is 
to  make  a  stick  which  shall  be  uniformly  strong.  This  is 
done  by  cutting  the  pieces  in  the  centre  of  the  panel,  and 
by  having  no  two  joints  in  either  chord  in  one  panel  ; 
though  in  long  spans  this  cannot  always  be  done. 

BRACES. 

The  whole  load  being         800,000  pounds, 
Each  truss  supports  400,000       « 

Each  set  of  braces  200,000       " 

Each  brace  (there  being  4)  50,000       " 

which  must  be  increased  for  inclination  as  follows  :  The 
length  of  diagonal  is  twenty-nine  feet,  (the  height  being 
twenty-five  and  length  15,)  whence 

25  to  29  as  50,000  to  58,000  Ibs.  ; 

which  would  need  fifty-eight  square  inches,  or  7  X  8  for 
compression  ;  which,  however,  is  quite  too  small  for  flexure. 
12  X  12  placed  in  the  formula  gives 

_     2240  X  l>d3 


or 

_      2240  X  12X1728 


=55,296  Ibs. 


In  practice,  smaller  braces  than  12  X  12  would  answer, 
because  the  four  braces  in  a  set  may  be  fastened  together, 


WOODEN   BRIDGES.  151 

making  a  post  of  four  pieces  8  X  12,  or  in  all  a  built  post 
of  44  X  12  inches ;  twelve  being  the  depth,  whence 

2249  X  44  X  1728 

the  forty-four  inches  being  made  by  blocking  the  braces 
four  inches  apart.  The  second  set  of  braces  are  to  be 
treated  in  the  same  manner,  the  weight  to  be  supported 
being  only  the  rectangle  included  by  those  braces;  i.  e. 
the  whole  bridge  and  load  less  the  two  end  panels. 

As  the  centre  of  the  span  is  approached,  the  pressure  on 
the  braces  becomes  very  small;  and  the  scantling  of  the 
braces  will  be  reduced  to  about  6x7  inches. 

RODS. 

The  weight  upon  the  first  set  of  rods  is  the  same  as  that 
upon  the  end  sets  of  braces  ;  in  the  present  case  800000 -f- 
2  =  400000  on  each  side  truss,  and  400000-^2  =  200000 
on  each  end ;  and  if  there  are  five  rods  in  each  set,  each  rod 
bears  40,000  Ibs.  Referring  to  the  table  on  p.  146,  oppo 
site  to  31,416  Ibs.,  is  the  diameter  If  inches ;  whence  the 
first  set  must  contain  five  rods,  of  If  inches  diameter. 
The  second  set  decrease  in  size  as  the  weight  is  lessened  by 
the  two  end  panels.  The  nut  and  washer  for  the  rod  are 
also  found  in  the  same  table. 

COUNTERBRACING. 

180.  When  a  load  is  placed  on  the  point  C',  fig.  64,  the 
truss  tends  to  sink  at  that  point,  and  a  corresponding  rise 
takes  place  at  C.  This  motion  changes  the  figure  A  B  C  E, 
from  a  rectangle  to  an  oblique  angled  figure ;  the  diagonal 
E  B  being  shortened,  and  A  C  lengthened.  This  motion  is 


152 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Fig.  64. 


easily  checked   by  the  introduction  of  the  counter    brace 
EB. 

The  action  which  this  timber  is  called  upon  to  resist, 
being  caused  by  the  moving  or  variable  load  on  one  panel, 
the  brace  must  resist  the  load  coming  thereon,  (say  fifteen 
feet,)  and  is  thus  the  same  size  as  the  brace  at  the  centre  of 
the  span. 

The  counter  braces  may  be  so  confined  between  the 
braces,  at  the  intersection,  as  not  to  move  laterally  or  verti 
cally,  but  must  not  be  fastened  to  the  braces ;  because  the 
action  of  the  separate  timbers  is  thus  trammelled. 

The  manner  of  adjusting  the  braces  and  counter  braces 
Fig.  67 c.  to  the  chord  is  shown  in  fig. 

67  C.  It  was  formerly  the 
custom  to  abut  the  braces 
against  a  block  on  one  side 
of  the  chord,  and  to  screw  the 
rod  against  a  block  on  the 
opposite  side  ;  the  whole 
strain  acting  to  crush  the 
chord  crosswise.  This  has 
been  remedied  by  the  arrange 
ment  shown  in  the  figure,  the 


WOODEN  BRIDGES. 


153 


two  blocks  being  cast  in  one 
piece  and  connected  by  a  small 
hollow  cylinder  passing  be 
tween  the  chord  sticks. 

This  system  is  known  as 
Howe's  bridge,  and  may  be 
seen  in  almost  any  section 
of  the  country ;  and  though 
in  many  cases  badly  propor 
tioned,  and  of  bad  material, 
if  properly  made  answers  a 
very  good  end. 

The  following  table  has 
been  formed  for  the  use  of 
engineers  and  builders,  giving, 
together  with  the  table  of  nuts 
and  washers,  all  dimensions 
required. 


Fig.  67  D. 


Fig.  67  E. 


Span. 

Rise. 

Panel. 

Chords. 

End 

braces. 

Centre 
braces. 

End  rod. 

Centre 
rod. 

50 

10 

7 

2  —  8  X  10 

7'2 

5X5 

2  —  U 

2  —  1 

75 

12 

9 

2  —  8  X  10 

8a 

5X5 

2  i-L 

2  —  1 

100 

15 

11 

3  —  8  X  10 

9* 

6X6 

2  —  if 

2  —  1 

150 

20 

13 

4  —  8  X  12 

102 

6X7 

3  —  2 

g  i 

200 

25 

15 

4  —  8  X  16 

12  2 

7X7 

5  —  2 

5  —  1 

154 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


PRATT  S    BRIDGE. 


Fig.  68. 


181.  Assume  the  following  data 
for  an  example  :  — 


Span        .        .        , 
Rise     .        .        . 
Panel       . 

Weight  per  lineal  ft. 


100  feet, 
.     12     " 
10     « 
2,500  Ibs. 


The  tension  on  the  lower,  or  the 
compression  on  the  upper  chord, 
will  be 


250000  X  100 
96 


=  260,417  Ibs. 


The  manner  of  dimensioning  the 
chord,  and  of  splicing,  is  the  same 
as  already  described  for  Howe's. 

SUSPENSION    RODS. 

The  first  sets  of  rods,  A  B,  A'  B', 
must  sustain  the  whole  weight  of 
the  bridge  and  load  ;  which  is 
250,000  Ibs.  Each  side  125,000 
Ibs.  ;  and  each  end  set  of  rods 
62,500  Ibs. ;  and  if  each  set  has 
four  rods,  each  rod  must  support 
15,625  Ibs. 

The  rod  being  inclined,  this 
amount  is  increased  by  the  fol 
lowing  proportion :  — 

12  (height)  to  15.8  (diagonal)  as  15,625 
to  20,573  Ibs. 

This  is  half-way  between  the  tubular  numbers  for  rods 


WOODEN   BRIDGES.  155 

of  1£  and  If  inches  in  diameter;  If  will  therefore  answer. 

The  next  set  of  rods  must  be  considered  as  supporting  the 

whole  load,  less  the  two  end  Fig.  68  A. 

panels,  and  so  on  as  already 

explained  for  Howe's  bridge. 

The  manner  of  applying  the 

rods   to  the  chords  is  shown 

in  fig.  68  A.     The  bevel  block 

should  be  connected  with  the 

block  at  the  foot  of  the  post, 

so  as  to  prevent  crushing  the 

chord. 

COUNTER  RODS. 

As  both  top  and  bottom  chords  are  always  used  in  this 
bridge,  the  counter  rods  have  only  the  variable  load  on  one 
panel  to  resist.  The  action  is,  in  amount,  the  same  as  that 
on  the  counter  braces  in  Howe's  bridge ;  but  acts  in  a  dif 
ferent  direction,  and  in  the  other  diagonal. 

The  weight  of  a  passing  load  cannot  be  more  than  two 
thousand  pounds  per  lineal  foot.  The  panel  being  ten  feet 
long,  the  whole  weight  coming  on  two  sets  of  counter  rods, 
(one  set  in  each  side  truss,)  is  twenty  thousand  pounds ;  or 
ten  thousand  pounds  on  each  set ;  and  if  there  are  put  three 
rods  in  each  set,  we  have  3,333  pounds  per  rod,  which  in 
crease  for  inclination  as  follows :  — 

12:  15.8::  3333:  4389  Ibs., 

requiring  a  rod  of  three  fourths  inch  diameter. 

The  posts  in  this  structure,  correspond  to  the  braces  in 
the  Howe  bridge  ;  only  being  vertical,  they  need  not  be  so 
large. 


156 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


182.    The  following  table  gives  all  the  dimensions  neces 
sary  for  proportioning  this  truss. 


Span. 

Rise. 

Chords. 

End  post. 

C  post. 

End  rod. 

Crod. 

Counter 
rod. 

50 

10 

2  —  8  X  10 

5X5 

42 

2  —  If 

2  — 

1  —  li 

75 

12 

2  —  8  X  10 

6X6 

52 

2  —  If 

2  

1  li 

100 

15 

3  —  8  X  10 

7  X    7 

62 

2  —  if 

2  — 

2—  ii 

125 

18 

3  —  8  X  10 

8X8 

62 

3  —  l| 

3  — 

2  —  if 

150. 

21 

4  —  8  X  12 

9X9 

62 

3  —  2j 

3  — 

3  —  U 

200 

24 

4  —  8  X  16 

10  X  10 

62 

till 

5  —  1 

3  —  ij 

And  the  following,  the  sizes  of  counter  rods,  for  different 
panels. 


Diameter  of  the  rod. 
One  in  a  set.    Two  per  set.    Three  per  set. 

u          u 


icn^tn  01 
panel. 

iieigni  01 
panel. 

diagonal 
of  panel. 

One  in  a 

10 

12 

16 

if 

11 

13 

17 

if 

12 

14 

18 

if 

13 

15 

20 

if 

14 

16 

21 

if 

15 

18 

23 

if 

16 

21 

26 

2 

18 

25 

27 

2 

u 

If 
If 
If 
If 


H 


The  advantage  possessed  by  this  bridge,  over  Howe's  plan, 
is  that  the  panel  diagonals  may  be  adjusted  by  the  screws; 
by  which  control  is  had  over  the  form  of  the  truss,  and  of 
the  duty  done  by  the  several  parts.  Change  of  form  cannot 
be  had  by  working  upon  verticals.  Howe's  bridge  must  be 
adjusted  by  wedging  the  braces  and  the  counter  braces. 

183.  The  manner  of  drawing  the  bevel  block  in  this 
bridge,  is  shown  in  fig.  68  b.  The  proportions  of  the  block 
depend  upon  the  proportions  of  the  panel ;  and  the  dimen 
sions,  upon  the  size  of  washer  band. 

Let  C  C  be  the  centre  line  of  the  post,  and  A  B  the  chord. 
Let  o  ra,  and  o  n,  be  the  panel  diagonals,  and  H  and  y,  the 
length  of  the  washers. 


WOODEN    BRIDGES. 
Fkr.  6SB. 


157 


The  depth  of  insertion  of  the  block  into  the  chord,  de 
pends  upon  the  horizontal  strain  upon  it.  In  a  span  of  one 
hundred  and  fifty  feet,  with  the  rods  at  an  angle  of  50°,  two 
inches  have  been  found  ample  at  the  end  of  the  truss,  and 
one  half  inch  at  centre. 

From  D,  perpendicular  to  mm,  lay  off  D  E ;  equal  to  H, 
also  from  E,  at  right  angles  to  n  n,  make  E  E'  =  y.  From 
E'  draw  the  vertical  E'  L. 

The  strain  upon  the  rod  o  m,  being  represented  by  o  m ; 
and  that  upon  on,  by  on,  the  resultant  is  shown,  both  in 
direction  and  amount,  by  o  V.  It  is  not  necessary  that  this 
should  pass  through  the  centre  of  the  post,  as  the  excess  of 
tension  on  o  m,  over  that  on  o  n,  is  absorbed  by  the  lower 
chord. 
NOTE.  —  Screwing  up  truss  bridges,  is  a  more  scientific  operation  thaa  is  gon- 

14 


158  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

erally  supposed.  Many  builders  commence  at  each  end,  and  lift  the  bridge  from 
the  scaffolding.  By  this  method  the  greater  part  of  the  load  is  often  borne  by 
a  few  of  the  end  sets  of  rods.  The  better  method  is  to  begin  at  the  centre  and 
work  both  ways  towards  the  ends,  being  sure  that  each  set  of  rods  does  its  duty 
before  the  next  is  touched.  The  lift  to  be  made  by  each  set  of  rods,  should  first 
be  calculated,  and  tested  while  screwing  up,  with  the  level. 

LATTICE    BRIDGES. 

184.  Town's  lattice,  consists  of  a  simple  lattice-work  of 
plank,  3  X  12  inches,  treenailed  together  at  an  angle  of  forty, 
forty-five,  or  fifty  degrees.  It  possesses  great  stiffness,  with 
out  by  any  means  having  the  material  disposed  in  the  best 
manner.  Such  bridges  might  well  be  made  by  the  mile, 
and  cut  off  to  order  according  to  the  span. 

The  improved  lattice,  by  Hermann  Haupt,  Esq.,  C.  E., 
avoids  all  of  the  evils  attendant  upon  the  common  lattice, 
and  gives  a  very  cheap,  strong,  and  rigid  bridge.  In  this 
plan  the  braces  are  placed  in  pairs,  with  vertical  tie  planks 
between  them ;  by  which  the  twisting  seen  in  the  common 
lattice,  is  removed.  The  braces  are  also  brought  to  the  ver 
tical,  as  the  point  of  support  is  reached,  by  which  a  good 
bearing  is  given  to  the  end  sets  of  timbers. 

To  vary  the  size  of  the  braces,  as  the  strain  upon  them 
decreases,  would  be  both  inconvenient  and  expensive ;  but 
the  same  effect  may  be  produced  by  varying  the  distance 
between  them,  making  it  greater  as  the  centre  is  approached. 

s.  w.  HALL'S  WOODEN  TRUSS  AND  ARCH  BRIDGE. 

Inverting  Mr.  Haupt's  design  for  a  lattice  of  improved 
construction,  (which  consists  of  vertical  ties  and  inclined 
braces,)  we  have  the  base  of  the  above-named  bridge  ;  where 
the  inclined  timbers  are  used  to  resist  tension,  as  below. 

This  being  a  very  good  plan,  and  the  arrangement  for 


WOODEN   BRIDGES.  159 

building  being  such  as  to  secure  the  thorough  execution  of 
the  work  in  its  most  minute  detail ;  it  is  thought  best  to 
extract  at  some  length  from  a  letter  from  the  inventor,  dated 
July  31st,  1856,  not  however  being  confined  to  the  matter 
therein. 

The  first  claim,  is  for  a  new  form  of  truss ,  formed  of  posts 
vertical,  or  nearly  so,  and  tension  pieces,  inclining  down 
wards  toward  the  centre ;  thus  differing  from  nearly  all 
other  plans.  Timber  resists  double  as  much  extension  as 
compression ;  and  when  large  enough  to  resist  the  simple 
tension,  does  not  have  to  be  increased  as  in  resisting  com 
pression  for  flexure;  but  requires  a  larger  allowance  for 
joints,  as  tension  tends  to  pull  the  joints  apart,  while  com 
pression  forces  them  together. 

The  following  result  was  obtained,  showing  the  superior 
strength  of  timber  work  in  resisting  by  tension.  Two  mod 
els,  containing  the  same  amount  of  timber,  were  tested. 
The  one  built  with  vertical  ties  and  braces,  broke  by  crip 
pling  the  brace,  under  2,400  Ibs. ;  while  that  constructed 
with  verticals  and  suspenders,  inclining  towards  the  centre, 
sustained  4,200  Ibs.  with  no  visible  change  of  form. 

The  second  claim  is  for  more  efficient  bearings  and  con 
nections  than  common,  and  this  with  less  cutting  away  of 
timber.  The  arch  and  arch  braces  have  a  full,  fair  bearing 
at  top  and  bottom.  The  first  sets  of  tension  braces,  (those 
extending  from  the  top  of  the  arch  braces  towards  the  cen 
tre,)  are  sustained  by  two  pins  at  each  joint ;  which  gives 
six  pin  bearings,  or  twelve  for  one  set  of  braces,  of  six  inches 
each,  (the  pin  being  two  inches  in  diameter,  and  plank  three 
inches  thick,)  equal  in  all,  to  seventy-two  inches  of  bearing 
surface  at  least,  for  each  five  feet  lineal  of  bridge,  or  one 
hundred  and  forty-four  inches  for  ten  feet. 

The  third  claim,  is  that  the  bearings,  at  joints,  are  central. 


160  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

and  that  the  shrinkage  of  the  timber  is  towards  and  not 
from  them  as  in  many  plans. 

The  pin  holes  are  bored  by  machinery  smooth  and  true ; 
the  treenails  when  of  wood  are  of  seasoned  oak  or  locust, 
turned  to  a  perfect  fit,  and  when  of  iron  are  made  hollow. 

These  bridges,  after  three  years,  stand  within  an  inch  of 
their  shape  as  framed  without  exception.  One  indeed  sup 
porting  an  aqueduct,  which  throws  upon  the  truss  a  constant 
load  of  2f  tons  per  foot,  not  including  the  weight  of  the 
bridge,  without  any  apparent  settling. 

The  connections  being  fast,  prevent  reaction  and  vibra 
tion  from  variable  loads,  the  strains  in  this  case  are  reversed, 
the  bridge  tending  to  spring  up  instead  of  settling. 

The  fourth  claim,  is  for  the  small  brace  connecting  the 
lower  with  the  intermediate  chord ;  by  which  additional 
connections  are  obtained,  and  smaller  timbers  rendered 
available. 

The  fifth  claim,  is  the  formation  of  a  stronger  chord  than 
by  the  plan  of  using  a  few  large  sticks.  The  chord  being 
made  of  a  great  number  of  small  pieces,  the  strength  is  of 
course  less  affected  at  any  one  point,  by  a  joint,  than  when 
only  a  few  pieces  are  used. 

In  the  bridges  built  by  the  above  engineer,  are  to  be  seen 
some  of  the  most  perfect  built  beams  in  the  country.  The 
following  conditions  being  observed,  the  most  uniform,  and 
highest  average  strength  possible  is  obtained. 

First.    To  cut  but  one  stick  in  any  one  panel. 

Second.    To  cut  no  stick  at  the  centre  of  the  bridge. 

Third.    To  place  every  joint  in  the  middle  of  the  collateral  piece. 

The  chords  are  cut  by  two  rows  of  pins,  two  inches  each  ; 
and  if  the  chord  be  fifteen  inches,  the  cutting  at  centre, 
where  there  is  no  joint,  is  but  four  fifteenths  of  the  whole 
section.  To  resist  the  parting  of  any  two  sticks,  there  is  the 


WOODEN  BRIDGES.  161 

resistance  to  shearing  of  ninety-six  pins ;  and  the  section  of 
each  being  three  square  inches,  the  whole  resistance  is  two 
hundred  and  eighty-eight  inches  of  area.  If  the  intermediate 
chord  has  the  same  number,  the  whole  area  to  resist  shear 
ing,  in  the  lower  chord,  is  five  hundred  and  seventy-six 
square  inches.  The  bearing  surface  of  each  pin  in  the 
chord  stick  is  2  X  3  inches,  or  six  inches  ;  and  96  X  6  =  576 : 
and  in  both  chords  1152  inches. 

Sq.  in. 

The  whole  chord  timber,  (both  chords,)  is  (6  X  3  X  14),  252 

In  the  intermediate  chord,  (6X3X12),  216 

Whole  timber  section,  468 
Deduct  4  pins  for  both  chords,  468  —  (4X2X3X6)  or 

468  —  144=  324 

Deduct  for  joints  3  X  10  +  3  X  8  or  324  —  54,  270 

Square  inches  of  available  area. 

Comparing  the  amount  thus  cut  away  with  that  cut  away 
in  other  plans,  we  have  the  following  figures :  — 

A.  Hall's  Bridge,  (actual  bridge,) 

B.  Howe's  bridge,  (actual  bridge,) 

C.  Page  163,  (Handbook  R.  R.  Construction,) 

D.  McCallum's,  (Susquehanna  bridge,)  -^fy 

The  sixth  claim,  is  the  peculiarly  convenient  form  for  ap 
plying  an  arch,  —  the  superiority  consisting  in  convenience 
for  attachment;  in  the  connections  being  less  affected  by 
shrinkage  than  when  posts  are  locked  into  arches ;  in  the 
timbers  not  being  weakened  by  cutting.  The  arch  is  loaded 
with  the  tension  timbers,  inwardly,  and  acts  as  a  general 
arch  brace,  transferring  at  once  all  of  the  several  tensions  to 
the  abutment,  thus  really  combining  the  arch  with  the  truss. 

The  liability  of  this  plan  to  decay,  certainly  appears  to 
be  less  than  that  of  most  plans  of  wooden  bridges  now  in 
use ;  as  will  be  plainly  seen  by  observing  the  position  of  the 

14* 


162  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

joints ;  falling  rain  finds  a  much  easier  access  to  almost 
any  other  joint  than  the  pin  hole.  The  timber  work  being 
made  of  plank,  all  the  timbers  are  small,  and  are  thus  much 
more  likely  to  be  sound. 

The  bridges  built  upon  this  plan 
upon  the  Alleghany  Valley,  and 
upon  the  Williamsport  and  Elmira 
roads,  illustrate  plainly  the  design. 
185.  Applying  arch  braces  to 
lattice  bridges,  has  suggested  The 
Arch-brace  truss  bridge^  in  which 
the  whole  strength  lies  in  a  series  of 
differently  inclined  braces,  extend 
ing  from  the  abutment  to  the  head 
of  each  post;  a  very  light  lattice 
being  used  to  prevent  reaction,  or 
as  a  counter-brace  or  stiffener. 
See  fig.  69. 

In  trusses  consisting  of  a  series 
of  triangles,  when  the  span  is 
large,  (150  to  200  feet,)  the  im 
mense  weight  coming  at  the  feet 
of  the  second  and  third  sets  of 
braces,  causes  a  settling  or  depress 
ing  at  twenty  or  thirty  feet  off  from 
the  abutment,  which  can  hardly  be 
removed.  The  remedy  for  such 
settling,  is  to  transfer  the  load  at 
once  to  the  abutment;  which  is 
completely  done  in  the  above- 
named  bridge.  Each  brace  does 
its  duty  directly  and  well.  Before 
the  lattice-work  is  fastened,  the 
bridge  should  be  loaded  with  a 


WOODEN  BRIDGES.  163 

maximum  load.  Then  by  fastening  the  diagonals,  the  recoil 
is  prevented;  and  the  effect  of  a  passing  load  is  to  ease 
the  counterbracing  lattice,  without  otherwise  affecting  the 
truss. 

NOTE.  — A  model  of  this  bridge,  made  by  the  writer,  of  the  following  dimen 
sions  :  — 

Length,  7  feet. 

Height,  1  foot. 

Width,  1     " 

Chords,  £  X  £  inch. 

Braces,  £  X  £     " 

Lattice,  £  X  ^Q  " 

Supported  2,500  Ibs.  at  centre,  besides  a  variable  load  of  150  Ibs.  applied  as  a 
rolling  weight  in  the  most  disadvantageous  manner.  It  represented  a  span  of 
one  hundred  and  fifty  feet,  and  according  to  Weisbach's  formula  for  testing  a 
model,  proved  the  actual  structure,  (as  far  as  can  be  proved  by  a  model,)  both 
strong  and  rigid  to  any  desired  amount.  The  longest  bridge  ever  built  upon 
this  principle,  was  that  of  Schaffhausen,  over  the  Rhine,  which  had  a  single 
span  of  three  hundred  and  ninety  feet.  This  bridge  was  not  stiff,  having  no 
lattice,  but  was  very  strong.  B.  H.  Latrobe,  Esq.  has  adopted  this  form  upon 
the  Baltimore  and  Ohio  Railroad. 

The  calculations  for  the  parts  of  this  bridge  are  as  fol 
lows  :  — — 

The  Span  being  150  feet, 

The  Rise  20      " 

The  Panel  15      « 

Weight  per  foot  of  bridge  and  load  3,000  Ibs. 

The   half  number  of  panels   is   five;   the   diagonals  of 
which,  neglecting  fractions,  are 


y/202+152  =  25  feet, 
~'  =  37  feet, 


164  HANDBOOK   OF  RAILROAD    CONSTRUCTION. 


y/202+602=r64feet, 


y/202+752=78feet. 

The  weight  upon  each  of  these  sets  of  braces,  is  the 
weight  of  the  length  of  one  panel ;  which,  in  the  present 
case,  is  3?000  X  15—45,000  Ibs.  As  there  is  a  brace  under 
each  chord  stick,  and  assuming  four  sticks  in  each  chord, 
we  divide  by  eight,  and  have,  in  round  numbers,  6,000  Ibs. 
per  brace ;  and  correcting  for  inclination,  as  follows,  we 
have  the  numbers  below. 

15  :  25  :  :  6000  :  10000 
15  :  37  :  :  6000  :  15000 
15  :  49  : :  6000  :  20000 
15  :  64  :  :  6000  :  25000 
15  :  78  :  :  6000  :  30000. 

The  last  column  has  the  several  weights  coming  upon 
the  different  braces  at  their  several  inclinations;  to  resist 
which,  the  scantling  might  be  very  small,  for  compression, 
but  flexure  requires  larger  dimensions. 

These  braces  should  be  confined  laterally  and  vertically, 
as  they  pass  each  post,  but  not  connected  therewith ;  as  this 
would  not  permit  a  free  action  of  the  brace,  without  strain 
ing  transversely  the  post. 

The  length  of  beam,  therefore,  in  which  flexure  is  to  be 
checked,  is  the  distance  between  posts  in  any  panel. 

In  panel  No.  1,  it  will  be  25  feet. 

u         ..     2       ••     ••     18     " 
u        u     3^      «     «     17     « 

«  u      4?        u      u      IQ      « 

«         «     5,      "     "     16     " 
and  applying  the  formula 

2240 Id*  _ 


WOODEN   BRIDGES. 


165 


we  get,  in  round  numbers,  the  following  dimensions,  the 
braces  being  bolted  and  blocked  together :  — 

For  the  1st  panel,  25  feet  long,  8  X  10 
"  2d  "  37  «  «  8  X  10 
"  3d  "  49  "  "  8  X  10 
"  4th  "  64  «  "  8  X  10 
"  oth  "  78  «  "  8  X  10. 

For  the  lattice-work,  a  double  course  on  each  side  of  each 
truss,  in  long  spans,  (150  to  200  feet) ;  and  a  single  course 
in  shorter  spans,  of  3  X  6  plank,  treenailed  at  intersections, 
is  ample. 


GENERAL    TABLE    OF   DIMENSIONS    FOR   ARCH    BRACE    TRUSS. 


Span. 

Rise. 

Chords. 

Ties. 

Braces. 

Lattice. 

50 

10 

2  —  8*  10 

1—8  X  10 

2  —  6  X  6 

2  X  9  or  3  X  6 

75 

12 

2  —  8  X  10 

1—  8X  10 

2  —  6  X  6 

2  X  9  or  3  X  6 

100 

15 

3_8  x  10 

2  —  8X  10 

3  —  6  X6 

2  X  9  or  3  X  6 

150 

20 

4  —  8  X  12 

3  —  8  X  10 

4  —  6  X  8 

2  X  9  or  3  X  6 

200 

25 

4  —  8  X  16 

3  —  8  X  10 

4  —  6  X9 

2  X  9  or  3  X  6 

166 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


Fie.  69  A. 


Fig.  69  A,  shows  the 
method  of  bringing  the 
arch  braces  to  the  chord. 
To  find  the  dimensions  of 
the  cast-iron  block,  make 
a  complete  drawing  of  all 
of  the  braces,  at  their 
proper  angles,  and  then 
draw  in  the  block  around 
the  feet,  as  shown  in  fig. 
69  B. 


NOTE.  —  The  centre  of  pressure 
of  the  braces  in  fig.  69  A,  is  not, 
as  might  seem,  at  C;  because  the 
vertical  components  of  the  forces, 
coming  down  the  brace,  are  much 
less  in  the  braces  at  small  angles 
than  in  those  at  the  end  of  the 
span.  The  load  applied  to  each 
brace  being  the  same,  and  the  in 
clines  being  found,  we  find  the  cen 
tre  of  pressure,  or  the  centre  of 
bridge  seat  as  follows  :  — 

The  length  of  the  brace  is  to  the 
vertical  height,  as  the  applied  load 
to  the  vertical  pressure.  In  fig. 
69  A,  we  have  the  following  lengths 
of  braces :  a,  25  ;  b,  37  ;  c,  49 ; 
d,  64 ;  e,  78 ;  /,  92  ;  and  g,  106  ; 
and  the  weights  corresponding 
thus, 


a,  25 

20  : 

6000  :  4800. 

b,  37 

20  : 

6000  :  3243. 

c,  49 

20  : 

6000  :  2450. 

d,  64 

20  : 

6000  :  1870. 

e,  78 

20  : 

6000  :  1540. 

/,  92 

20  : 

6000  :  1304. 

9,  106 

20  : 

6000  :  1132. 

WOODEN   BRIDGES. 


167 


• 69B- 


In  fig.  69  A,  assume  the  foot  of  the  fifth  brace  (B)  as  the 
centre  of  pressure,  and  adding  the  moments,  (or  products 
of  vertical  components  on  the  braces  by  their  distance  from 
B,)  and  we  have  the  sum  on  the  land  side  18,928,  and  on 
the  water  side  16,930 ;  showing  that  the  centre  is  taken  too 
far  from  the  land  side.  In  the  same  manner  A  will  be 
found  too  far  from  the  land  side.  A  third  trial  will  give 
the  place. 

Fig.  69  B,  shows 
the  manner  of 
splicing  the  arch 
braces ;  being  sub 
jected  to  compres 
sion,  they  are 
spliced  in  the 
same  manner  as 
the  upper  chords. 
Fig.  C,  shows  the 

lower      chord  Fig.  69 c. 

spliced.     Figs.  D  and  E,  the  connection  of  the  posts,  chord, 
and  lattice.      Figs.  F,  G,  and  H,  the  casting  for  applying 


Fig.  69  D. 


Fig.  69  E. 


Fig.  69  F. 


Fig.  69  G. 


Fig.  69  H. 


163  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

the  upper  end  of  the  arch  brace  to  the  chord.  Fig.  69  K, 
the  method  of  supporting  the  tracks  at  the  end  of  the  span, 
where  the  arch  braces  will  not  allow  the  floor  beams  to 
bear  upon  the  lower  chord. 

McCALLUJt'S    PATENT    RAILROAD    BRIDGE. 

186.  This  bridge  represents  a 
class  of  structures  in  which  the 
upper  chord  is  curved  upwards 
(7£  feet  in  200  in  the  Susquehanna 
bridge,  New  York  and  Erie  Rail 
road),  which  curved  chord  has  the 
effect  of  distributing  an  applied 
load  at  once  to  all  of  the  braces 
directly,  by  means  of  the  chord,  as 
well  as  indirectly,  by  means  of  the 
braces,  as  in  the  common  trusses. 
To  this  bridge  is  applied  the  arch 
braces  AB,  AB,  fig.  70,  which 
serves  to  aid  the  2d,  3d,  and  4th 
pair  of  diagonal  braces  in  bearing 
their  load. 

The  great  distributing  power  of 
the  curved  chord,  is  shown  by  the 
fact  that  a  bridge  of  125  feet  span, 
actually  supported  a  railroad  train 
before  the  diagonal  bracing  was 
introduced.  The  whole  strain  was 
thrown  through  the  curved  chord 
and  arch  braces  to  the  abutments. 
The  bridge  is  counterbraced  by  the 
pieces  d  d  and  d  d,  adjustable  by 
screws  at  the  ends. 

The  following  test  was  applied 
to  a  span  of  190  feet  of  this  plan 


WOODEN   BRIDGES.  169 

of  bridge.     Placing  the  load  as  near  as  possible  to  the  cen 
tre,  the  following  deflections  were  produced. 

Load.  Deflection. 

41.40  tons,  0.013  feet, 

95.35  tons,  0.038  feet, 

140.70  tons,  0.061  feet, 

187.20  tons,  0.061  feet. 

Upon  removing  the  load,  the  bridge  entirely  recovered  its 
form. 

187.  As  the  span  increases,  the  benefit  derived  from  the 
curved  chord  also  augments ;  and  though  in  the  latter  part 
of  the  present  chapter  its  application  to  small  spans  is  shown, 
it  may  not  be  worth  while  to  adopt  it. 

Bridges  transferring  the  load  directly,  from  each  panel  to 
the  abutment,  would  not  be  aided,  to  an  amount  worth  the 
increased  expense,  by  adopting  the  curved  top  chord. 

in  case  of  any  settling  at  the  centre  of  the  span,  the 
reverse  effect  is  seen  from  that  produced  in  a  truss  with  hor 
izontal  chords ;  i.  e.,  when  the  ends  of  the  upper  chords  in 
the  latter  draw  in,  those  of  the  former  push  out ;  and  when 
in  such  bridges,  arch  braces  are  not  used,  the  top  chords  of 
adjoining  spans  must  be  wedged  apart,  in  place  of  tying 
together  as  in  common  plans,  over  the  centre  of  the  piers. 

THE  ARCH. 

188.  The  arch  has  been  applied  to  long  spans  for  a  great 
while,  and  when  care  has  been  taken  to  prevent  flexure, 
answers  very  well.     The  repair  of  such  bridges,  if  any  of 
the  arch  timbers  decay,  is  difficult ;  but  is  effected,  in  the 
largest  arches. 

The  most  correct  ideas  on  wooden  arch  bridge  building, 
are  to  be  found  in  Weibeking's  Traite  dune  parte  essential 
de  construire  les  grandes  pents  en  charpente.  This  engineer, 

15 


170  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

(General  Director  of  Roads  and  Bridges  in  Bavaria,)  has 
built  a  great  number  of  wooden  arches  of  the  best  descrip 
tion,  which  show  him  to  be  master  of  both  the  science  and 
the  art. 

The  general  plan  of  his  bridges  is  shown  in  fig.  71.     They 

Fig.  71. 


consist  of  curved  ribs  formed  of  long  pieces  scarfed  and 
bolted  together,  from  which  the  road-way  is  supported  by 
posts. 

The  bridges  of  Neucettringin,  Freysingin,  Bamberg, 
Scharding,  Wertach,  Vilshoven,  and  Altenmarkt,  all  testify 
to  the  good  judgment  of  this  man.  The  spans  vary  from 
one  hundred  to  two  hundred  feet ;  and  the  width  from 
twenty-five  to  thirty-two  feet.  The  proportions  which  he 
gives  for  the  ratio  of  rise  to  span,  are  valuable  ;  as  they  are 
the  result  of  his  own  experience.  He  states,  generally,  that 
one  tenth  of  the  span  is  the  best  rise  ;  but  that  for  conven 
ience,  it  is  better  to  keep  it  lower.  The  following  table 
shows  the  dimensions  he  has  adopted  in  practice. 


WOODEN  BRIDGES. 


171 


189. 


Name. 

Span. 

Rise. 

Width. 

Rod  of 
Arch. 

Scantling  of 
Arch. 

Bamberg, 

208 

16.9 

32 

422 

13^ 

-  X  15} 

Scharding, 

194 

18.8 

25 

258 

12\ 

X  15} 

Vilshoven, 

179 

11.1 

27 

378 

13t 

-  X  15} 

Freysingin, 

153 

11.6 

25 

246 

12j 

-  X  14} 

Ettringin, 

139 

8.0 

25 

305 

Ifc 

-  X  15} 

Ersingin, 

126 

7.0 

25 

285 

llj 

-  x  u} 

Augsberg, 

114 

10.6 

25£ 

158 

12I 

^x  u} 

Neucettringin, 

103 

6.8 

25 

200 

131  X  15} 

The  last  column  shows  the  scantling  of  the  arch  timbers ; 
these  being  placed  three  deep,  in  spans  of  less  than  150  feet ; 
and  in  larger  spans,  3  deep  at  centre,  and  5  deep  at  ends. 
Mr.  Weibeking's  formula  for  determining  the  scantling  of 
ribs,  is  as  follows :  — 


.0011  =  Scantling  in  sq.  ft. 


En 


Where  R  is  the  rise  of  the  arch  ; 
w,  the  number  of  ribs  ; 
Wy  width  of  bridge ; 
and  S,  span  of  bridge. 

EXAMPLE.  —  Required  the  scantling  of  the  ribs  of  a  bridge 
of  300  feet  span,  20  feet  wide,  and  30  feet  high.  The  for 
mula  becomes,  — 

20  X  22500 


30 


X  .0011  =  16Jsq.  feet  of 


section,  of  all  of  the  arches ;  or  two  parallel  arches,  2J  feet 
wide,  by  3J  feet  deep  each. 

From  100  to  150  feet  span,  he  makes  the  rise  ^  span, 

«      150  to  200         "  "                  A      " 

"      200  to  300         "  "                 ^5      " 

«      300  to  400         «  "                  ^      " 

«      400  to  500         "  "                  •         " 


172  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

190.  The  bridge  built  by  Mr.  Burr  across  the  Delaware 
at  Trenton,  New  Jersey,  is  a  good  specimen  of  an  arch.     It 
is  composed  of  white  pine  planks,  from  thirty-five  to  fifty 
feet  long,  and  of  a  scantling  4  X  12.     These  planks  are  laid 
close  together,  breaking  joint,  having  an  entire   depth  of 
three  feet.     The  arches  are  stiffened  by  horizontal  tie  beams, 
supporting  the  road-way,  and  by  diagonal  bracing.     The 
spans  are  160,  180,  and  200  feet,  and  the  rise  twenty-seven 
feet. 

191.  The  bridge  over  the   Susquehanna,  at   Columbia/ 
built  in  the  same  manner,  consists  of  twenty-nine  arches, 
each  two  hundred  feet  clear  span,  supported  on  two  abut 
ments  and  twenty-eight  stone  piers.     The  clear  water-way 
of  this  bridge  is  5,800  feet ;  and  the  entire  length,  including 
piers  and  abutments,  one  and  one  fourth  miles.     There  are 
three  sets  of  arches,  which  allow  of  two  carriage  roads  and 
one  railroad,  the  whole  width  being  thirty  feet. 

192.  An  arch  to  support  a  passing  railroad  train  must  be 
very  rigid.     It  is  customary  to  connect  them  with  a  light 
truss,  which  effectually  counter  braces  the  arch,  and  prevents 
that  change  of  form  which  would  otherwise  take  place ;  de 
pending  entirely  upon  the  arch  for  strength. 

Wherever  the  load  is  applied,  the  arch  tends  to  sink,  and 
a  corresponding  rise  takes  place  at  the  opposite  point.  A 
load  placed  at  E,  fig.  71,  settles  the  arch  at  that  point  and 
causes  it  to  rise  at  C.  A  load  placed  at  the  curve  of  the 
arch  depresses  the  centre,  and  elevates  the  haunches.  To 
counteract  these  movements  a  light,  stiffening  frame  may 
be  used,  its  strength  being  able  to  resist  the  variable  load 
passing  over  the  bridge.  The  strain  thrown  by  the  arch 
upon  the  truss,  advances  from  the  opposite  end  to  meet  the 
train,  passes  it  at  the  centre,  and  finally  goes  off  from  the 
bridge  behind  the  load. 


WOODEN   BRIDGES.  173 

When  the  arch  is  the  truss,  or  when  a  truss  is  made  with 
curved  chords,  the  counteracting  effect  of  the  truss  is  not 
completely  obtained.  We  should  not  depend  upon  the 
curved  chord  as  an  arch,  but  only  as  a  member  of  the  truss. 

193.  Many  combinations  of  arch  and  truss   have  been 
built  in  America  for  railroad  bridges.     The  principle  of  con 
necting  the  two  systems  is  by  some  thought  bad,  as  they 
can  hardly  be  made  to  bear  equal  parts  of  the  load  ;  whence 
each  must  have  more  than  half  the  necessary  strength  of  the 
whole.     Others  maintain  that  by  a  proper  arrangement  of 
parts  a  perfect  adjustment  may  be  made,  by  which  the  load 
may  be  placed  more  or  less  on  either.     There  seems  to  be 
no  very  good  reason  why  the  two  systems  should  be  com 
bined,  as  either  may  be  made  strong  enough  to  bear  the 
largest  loads. 

Both  arches  and  arch  braces,  however,  are  very  usefully 
applied  to  bridges  which  have  been  made  too  light. 

194.  The  manner  of  applying  arches  is  well  shown  in 
the  bridges  of  the  Pennsylvania  Central  Railroad,  built  by 
Hermann  Haupt,  Esq. 

These  bridges  are  on  Howe's  plan,  to  which  have  been 
added  strong  wooden  arches.  The  systems  are  connected 
by  adjusting  the  counter  braces  against  the  arch  by  set 
screws.  The  arrangement  is  simple  and  effectual.  The 
name  of  the  builder  is  sufficient  to  warrant  the  ability  of  the 
bridge. 

195.  However  nicely  we  may  form  an  arch,  it  will  settle 
more  or  less  when  the  scaffolding  is  removed,  according  to 
its  flatness;   which  depression  increases  with  time.      Mr. 

Weibeking  expresses  it  in  inches  as  follows :  — 

T-> 

0.806  « 
o 

Whence  ./?,  shows  the  rise, 
and  /S,  shows  the  span. 
15* 


174  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 

To  allow  for  this  settling,  the  curve  when  laid  down  on  the 
platform  for  building  the  arch,  should  be  made  a  little  more 
convex  than  the  completed  arch  is  required  to  be ;  the 
amount  of  excess  being  that  shown  by  the  formula. 

As  a  bridge  composed  of  a  curved  rib  when  the  span  is 
large  yields  at  D,  C,  and  E,  fig.  71,  when  the  load  is  applied 
in  the  middle,  the  strength  must  of  course  be  increased  by 
increasing  the  depth  of  the  rib ;  and  not  to  make  this  too 
heavy,  a  framed  or  built  beam  should  be  used  as  in  fig.  72. 

Fig.  72. 


Here  it  must  be  remembered  that  the  two  ribs  must  be  so 
framed  as  to  resist  both  tension  and  compression ;  for  when 
a  load  is  placed  at  D,  the  lower  rib  will  be  extended  at  d, 
and  compressed  at  c',  and  e ;  while  the  upper  one  will  be 
compressed  at  D,  and  extended  at  C  and  E. 

OF   THE   ROAD-WAY. 

196.  The  flooring  of  any  system  is  about  the  same  ;  con 
sisting  of  transverse  floor  beams,  placed  either  on  the  top  or 
bottom  chords,  (according  as  the  road-way  is  more  or  less 
elevated  above  the  water-way,)  which  support  longitudinal 
timbers,  upon  which  are  placed  cross-ties.  In  some  cases, 
two  curves  of  diagonal  plank  have  been  placed  across  the 
floor  beams,  spiked  at  right  angles  to  each  other,  by  which 
the  bridge  is  considerably  stiffened  laterally. 


WOODEN  BRIDGES. 


175 


General  dimensions  for  the  floor  may  be  thus :  — 

Transverse  timbers,  3  feet  from  centre  to  centre,  8X14 
Track  strings,  notched  2  inches  to  floor  beams,  12X14 
Cross-ties  placed  one  foot  apart,  (clear,)  3  X  6 


Fig.  73. 


LATERAL  BRACING. 

197.  To  prevent  vibration  in  a 
horizontal  direction,   a  system    of 
triangular    bracing    is    necessary 
The    chief    pressure    upon    these 
braces    is   caused    by   wind ;    and 
may  be  found  by  considering  the 
bridge    as   turned   over   upon   the 
side,   and   loaded   with    a   weight 
equal  to  the  maximum  pressure  of 
the  wind,  which  may  be  taken  as 
forty  pounds  per  square  foot. 

It  is  unnecessary  to  vary  the 
size  of  these  braces,  except  in  very 
long  spans,  when  they  should  in 
crease  from  the  centre  to  the  ends. 
For  short  spans,  (less  than  one 
hundred  feet,)  a  brace  5  X  5  is 
large  enough.  For  larger  spans 
7  X  7  is  sufficient. 

198.  Diagonal  bracing,  when  it 
can  be  introduced,  is  a  very  desir 
able  part  of  a  bridge.     When  the 
road  is  on  the  lower   chord   this 
cannot  have  place  in  full,  but  may 
be  applied  as  in  fig.  74. 


176  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Fig.  74. 


By  increasing  the  height  of  truss  in  any  bridge,  the  ten 
sion  and  compression  on  the  chords  is  lessened ;  but  the 
length  of  posts  and  rods  is  increased.  As  a  general  thing, 
one  eighth  of  the  span  gives  the  best  results. 

199.  In  framing  a  large  bridge,  it  is  customary  to  cut  the 
top  chord  sticks  a  little  longer  than  to  dimension ;  to  allow 
for  compression  in  settling. 

200.  Bridges  in  exposed  situations  have  been  sometimes 
blown  off  from  the  masonry.     If  a  bridge  slides  off  from  the 
masonry,  the  whole  force  of  the  wind  must  be  fifteen  twenty- 
fourths  of  the  whole  weight  of  the  bridge  ;  but  if,  as  is  gen 
erally  the  case,  the  masonry  is  rough,  (and  not  hammered,) 
no  amount  of  wind  will  cause  the  bridge  to  slide. 

The  bridge  will  upset,  turning  about  its  lower  edge,  when 
the  whole  pressure  of  the  wind,  multiplied  by  half  the  height 
of  truss,  overbalances  the  whole  weight,  multiplied  by  the 
half  width.  In  very  exposed  places  the  rod  A  D,  fig.  74, 
answers  a  very  good  end ;  when  the  road  is  upon  the  upper 
chord,  and  a  rod  from  B  to  the  masonry,  when  upon  the 
lower. 


WOODEN   BRIDGES.  177 


OBLIQUE    BRIDGES. 

201.  The  effect  of  running  a  train  over  a  skew  bridge,  is 
to  depress  one  side  before  the  other;  as  the  load  comes 
upon  the  centre  of  one  truss  before  it  does  upon  the  opposite 
one.     This  produces  a  side  rocking  in  the  engine,  dangerous 
alike  to  the  bridge  and  to  itself. 

The  floor  timbers  transferring  the  load  to  the  chords 
should  not  be  at  right  angles  to  the  axis  of  the  road,  but 
parallel  to  the  abutment,  Thus  in  fig.  75,  a  wheel  at  B, 
throws  one  third  of  rig.  75.  Fig.  75  A. 

its  weight  upon  the 
abutment  at  E ; 
and  two  thirds 
upon  the  chord  at 
C ;  while  in  fig. 
75  A,  the  wheel  at 
B,  throws  two 
thirds  of  the  load  upon  C,  but  one  third  also  upon  D. 

202.  In  a  very  long,  oblique  span,  the  floor  timbers  may  be 
arranged  as  in  fig.  rig.  76. 

76,  that  is,  in 
clined  at  the  en 
trance  and  exit  of 
the  bridge,  but  at 
right  angles  at  the 
middle  of  the  span. 

203.  The  preservation  of  timber  in  wooden  bridges  may 
be  accomplished   by  covering  with  boards,  whitewashing, 
painting,  and  by  Kyanizing.     Covering  and  whitewashing 
are  the  best,  if  care  is  taken  to  prevent  dry  rot  by  giving  a 
good   circulation  of   air   about   the   timbers.     The    oil   in 
paints  prevents  the  escape  of  moisture  from  within  as  well 
as  the  entrance  of  that  from  without ;  and  should  not  be 


178  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

used  unless  the  wood  is  well  seasoned.  The  best  plan  is  to 
thoroughly  whitewash  and  cover  the  frame  of  the  bridge, 
and  to  paint  the  article  of  the  covering. 

204.  In    framing   two    or   more   continuous    spans,   the 
chords  should  always  be  connected  over  the  piers ;  as  there 
is   thus    given    something    for    the   upper   chords   to    pull 
against,  and  a  counter  thrust  for  the  lower. 

205.  Bridges  should  never,  when  it  can  be  avoided,  be 
placed  either  upon  a  curve  or  upon  a  grade  ;  particularly 
upon  the  former,  as  the  effect  of  a   load   is  thereby  very 
much  increased,  in  the  first  case  causing  a  lateral,  and  in 
the  second  a  vertical  shock. 

PILE    BRIDGING. 

206.  In  shallow  water,  in  marshes,  and  in  similar  situa 
tions,   where    an   embankment   would   be   expensive,   pile 
bridging  is  very  useful.     Indeed,  whenever  we  are  at  liberty 
to  obstruct  the  passage  beneath  the  road,  it  is  well  to  adopt 
this   system,  unless  over  twenty  feet  high.     It  is  cheaper 
than  any  other,  easier  to  repair,  the  parts  are  quite  inde 
pendent  of  each  other,  and  such  bridges  last  full  as  long  as 
other  wooden  structures. 

Different  plans  for  pile  bridging  are  given  in  figs.  77  to 
82.  Figs.  77  to  81  show  plans  for  temporary  pile  work,  to 
be  used  during  construction.  Nothing  lighter  than  fig.  82, 

Fig.  78. 


WOODEN  BRIDGES. 


179 


Fig.  79. 


Fig.  80. 


180 


HANDBOOK   OF  RAILROAD  CONSTRUCTION. 


ought  to  be  permanently  used.  A  pile  bridge  upon  a  curve 
may  need  stronger  lateral  bracing  upon  the  convex,  than 
upon  the  concave  side  of  the  curve ;  and  also  in  running 
water ;  in  which  cases,  such  a  form  as  fig.  31  may  do  good 
service. 

(For  pile-driving,  and  for  proper  dimensions,  see  chap. 
XII.) 

TRESTLING. 

207.  Trestling  is  a  system  of  vertical  posts,  and  of  caps 
and  braces,  used  both  for  temporary  and  for  permanent 
works ;  temporarily  to  pass  a  road  over  low  ground  where 
embankments  are  to  be  made,  and  permanently  over  deep, 
dry  gorges,  where  the  amount  of  earthwork  or  masonry 


would  be  too  great. 

Fig   83. 


Fig.  84. 


American  railroads 
show  all  sizes  and 
arrangements  of  trest- 
ling,  from  twenty  to 
two  hundred  feet  high. 
Figs.  83  and  84  show 
temporary  works,  and 
fig.  85  permanent. 

The  main  part  of 
the  design  in  trestles 
is  to  connect  the  several  posts 
and  caps  by  well-formed  tri 
angles  ;  the  equilateral  being 
the  best. 

The  finest  example  of  this 
system  of  building  is  the  Gene- 
see  high  bridge,  over  Genesee 
River  near  Portage ville,  on  the 
Buffalo  and  New  York  Rail 
road  ;  built  by  H.  C.  Seymour. 


WOODEN  BRIDGES. 
Fig.  85. 


181 


Esq.  It  is  eight  hundred  feet  long,  and  two  hundred 
and  thirty  feet  above  the  river.  It  has  eight  stone 
piers,  thirty  feet  high,  upon  which  are  placed  trestles  one 
hundred  and  ninety  feet  high,  seventy-five  feet  wide  at 
base,  and  twenty-five  at  top.  Upon  the  top  of  all  is  placed 
a  bridge  fourteen  feet  high.  To  build  this  viaduct  was  used 
1,500,000  feet,  board  measure  of  timber,  which  covered,  when 
standing,  two  hundred  and  fifty  acres  ;  also,  sixty  tons  of  bolts. 
The  whole  time  occupied  in  building  was  but  eighteen 
months,  the  whole  cost  being  $140,000. 

DRAWBRIDGES. 

208.    In  crossing  rivers  or  bays  open  to  navigation,  it  is 
required  from  any  companies  building  a  bridge,  to  leave  a 

16 


182 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  86. 


free  passage  for  shipping. 
This  is  done  by  making  that 
part  of  the  bridge  over  the 
channel  movable  ;  (a  draw). 
Draws  may  lift  up,  (being 
counterbalanced,)  may  slide 
back  upon  the  fixed  part  of 
the  bridge,  or  may  turn  on  a 
pivot.  Fig.  86  shows  a 
draw  much  used  at  present, 
and  answering  every  pur 
pose.  Each  half  of  the 
movable  part  must  be  cal 
culated  as  a  small  bridge. 
The  rods  ccc  support  the 
overhanging  part  of  the 
draw  while  open.  The 
whole  revolves  upon  a  cen 
tre  pin  and  a  set  of  rollers. 

CENTRES. 

209.  Centres  are  tempo 
rary  wooden  frames,  used  in 
the  construction  of  stone 
arches.  Their  duty  is  to 
hold  the  masonry,  while  it  is 
unable  to  support  itself. 

For  arches  from  five  to 
fifteen  feet  span,  a  centre 
made  of  boards  or  planks, 
fig.  87,  is  all  that  is  neces 
sary.  For  longer  spans, 
when  the  ground  beneath 


WOODEN  BRIDGES. 

Kg.  87. 


183 


the  arch  can  be  used,  the  form,  fig.  88,  answers  well.    When 

Fig.  88. 


there  is  no  support  but  the  abutments  or  piers,  something 
similar  to  fig.  89  must  be  adopted.  This  is  the  plan 
adopted  by  George  Rennie,  chief  engineer  at  the  Waterloo 
bridge  over  the  Thames  at  London. 

Centres  are  strained  in  a  different  manner  as  the  arch 
progresses ;  first  at  the  haunches,  and  last  at  the  crown. 
Excess  of  weight  at  any  point  causes  a  settling  at  such, 


184 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  89. 


and  a  rise  takes  place  at  some  other  place.  By  loading  the 
arch  temporarily,  such  motions  are  checked. 

These  frames  are  placed  vertically  upon  the  pieces  F  F, 
which  being  connected  with  the  braces  D  D  by  the  folding 
wedges  c  c,  admit  of  adjustment  of  the  height  of  the  centre. 
The  distance  between  the  ribbed  frames  depends  upon  the 
form  of  the  arch,  and  the  span,  or  upon  the  weight  to  be 
supported ;  varying  from  one  to  four  feet.  The  centres  are 
covered  with  a  course  of  narrow  plank,  placed  parallel  with 
the  axis  of  the  arch,  upon  which  the  barriers  rest. 

210.  The  method  of  putting  a  bridge  upon  the  masonry 
is  shown  in  figs.  90,  and  91 ;  the  former  when  the  road-way 
is  upon  the  upper,  and  the  latter  when  upon  the  lower 
chord. 


WOODEN  BRIDGES. 


185 


Fig.  90. 


Pig.  91. 


211.  In  figs.  92  to  100,  are  given  several  plans  for  spans 
from  five  to  seventy-five  feet.  Fig.  92,  shows  the  simple 
beam  braced  beneath  with  diagonal  plank ;  the  bolts  passing 
through  the  ties,  stringers,  and  braces.  The  stringers  are 
bolted  to  the  wall  plates,  and  when  the  bridge  is  upon  a 
curve  notched  also,  by  cutting  the  bolster.  Fig.  92  A 
shows  the  plan.  This  form  answers  for  openings  from  five 
to  twenty  feet.  From  fifteen  to  thirty  feet,  we  may  n«e 
figs.  94,  95,  96,  and  97.  From  twenty-five,  to  fifty  and 
sixty  feet,  figs.  93,  97,  and  98.  And  from  fifty  to  seventy- 
five  feet,  figs.  99  and  100. 

The  following  tables  give  reliable  dimensions  for  bridges 
upon  the  above  plans, 

16* 


186  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  92.    6  to  20  feet. 


Fig.  92  A. 


Span. 

Bolsters. 

Stringers. 

Ties. 

Braces. 

Bolts. 

5 

12X12 

12  X12 

6X10 

2X10 

1  inch 

10 

12  X  12 

12  X  13 

6X10 

2X10 

1  inch 

15 

14X14 

12X18 

6X10 

2X10 

1  inch 

20 

14X14 

12X21 

6X10 

2X10 

1  inch. 

The  ties  being  notched   three  inches  on   to  the  stringers, 
without  cutting  the  latter. 


WOODEN  BRIDGES, 


Fig.  95.    15  to  30  feet. 


Span.  Rise.  Bolster. 

15         6  12X12 

20         7  14  X  H 

25         8  14X14 

30  10  15X15 


2  — 5X  10       H  inch, 


Fig.  96.    15  to  30  feet. 


Span. 

Rise. 

Stringer. 

Post. 

Rod. 

15 

5 

12X12 

8X    8 

i* 

20 

6 

12X13 

9X    9 

U 

25 

7 

12X15 

10  X  10 

i* 

30 

8 

12X18 

10X12 

if 

188  HANDBOOK   OP  RAILROAD   CONSTRUCTION. 

Fig,  94.    15  to  30  feet. 


Span. 

Rise. 

Stringer. 

Braces. 

Rods.              Lattice. 

15 

5 

2  —  8X8 

2  —  5X5 

1           2X6 

20 

6 

2  —  8X9 

2  —  5X  6 

li         2X8 

25 

7 

2  —  8X  10 

2  —  5X  8 

If         2X9 

30 

9 

2  —  8X  12 

2-5X9 

li        2  X  10 

• 

| 

Fig.  97. 

• 

15  to  80  feet. 

• 

•1 

• 

Span. 

• 

Rise. 

Stringer. 

• 

Post. 

Rod.             Braces. 

15 

5 

2  —  8X8 

8X8 

1           4X5 

20 

6 

2  —  8X9 

9X9 

1J        4X6 

25 

7 

2  —  8X10 

10  X  10 

H         5X6 

30 

9 

2  —  8X12 

10X12 

li         6X6 

i^^^^^ 

Fig.  93. 

25  to  50  feet. 

m 

• 

••BBS 

• 

KnlSSHS 

\v 

r    ' 

.//< 

/v\ 

I. 

// 

\  v/  \ 

S,  '/    ^\ 

/•'  \\ 

•HSJBMMiBag  iSiassfSsaeaSSSu      ^SSEuSsaESSauSaSSi      ^SSStSS^ 

HBBM^^9^IBH5Sfl|HBE^B^E^9^@fii^3S@^HBll 

Span. 

Ride. 

Chords. 

Braces. 

Posts.              Rods. 

25 

8 

2  —  6X8 

6X6 

6X8          1 

40 

10 

2  —  7X9 

6X7 

8X8          1£ 

50 

10 

2  —  8X10 

6X8 

8X10        1^ 

WOODEN  BRIDGES. 


Fig.  97.    25  to  50  feet. 


Fig.  98.    25  to  50  feet. 


189 


Span. 

Rise. 

Chords. 

Posts. 

Braces. 

Rods. 

25 

8 

2  —  6X8 

8X8 

5X5, 

11  or  2-  J 

40 

10 

2  —  7X9 

9X9 

5X8 

If  or  2-1, 

50 

10 

2_8X  10 

10x10 

6X8 

If  or  2  —  1- 

Span. 

Rise. 

Chords. 

Posts. 

Braces. 

25 

8 

2—6 

X 

8 

6 

X 

8 

5 

X 

5 

40 

10 

2—7 

X 

9 

6 

X 

9 

5 

X 

8 

50 

10 

2  —  8 

X 

10 

6 

X 

12 

5 

X 

10 

Rods. 

2_1  or  1  —  If 
2  — IJorl  — If 
2  — 11  or  1—1 J 


Fig.  99.  60  to  75  feet. 


Span. 

Rise. 

Chord. 

Posts.                           Braces. 

Lattice. 

50 

8 

2. 

8X 

10 

1 

—  8 

X 

10 

2  —  6X7 

2 

X6 

60 

9 

2. 

8X 

10 

1 

—  8 

X 

10 

2  —  6X7 

2 

X6 

75 

10 

3. 

8X 

10 

2 

—  8 

X 

10 

3  —  6X8 

2 

X6 

Fig.  100.  50  to  75  feet. 


190  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

Spa*.  Rise.  Chord,.  Posts.  Braces. 


No.          .  2. 

50      8     2  —  8X10     1  —  8X10     2  —  6x7     5x5     1£      1 
60       9     2  —  8X10     1  —  8X10     2  —  6x7     5x5     If      1£ 
75     10     3  —  8X10     2  —  8X10     2  —  6x8     5X6     If      1J 

212.  In  dimensioning  small  bridges,  like  the  above,  in 
estimating  the  maximum  load,  more  regard  must  be  given 
to  the  weight  of  momentary  loads  than  (as  in  large  bridges) 
the  weight  per  lineal  foot,  as  the  weight  of  the  bridge  itself, 
when  under  fifty  or  sixty  feet  span,  is  inconsiderable.  The 
greatest  load  that  can  come  upon  a  single  post  or  rod,  is 
that  from  the  driving  wheels  of  a  locomotive.  If  the  whole 
engine  weighs  forty  tons,  there  will  be  ten  tons  on  each 
pair  of  drivers,  or  five  tons  or  11,200  Ibs.  on  each  wheel  ; 
which,  being  applied  over  a  length  of  ten  feet  only,  may  be 
considered  as  at  a  single  point,  and  all  parts  must  be  able 
to  bear  such  load.  In  large  spans,  where  the  weight  is 
great,  if  the  truss  is  strong  enough  to  support  the  bridge 
and  load,  it  will  safely  resist  the  effects  of  a  sudden  appli 
cation  of  passing  trains. 

NOTE.  —  On  the  Static  and  Dynamic  deflection  of  Bridges.  Considerable  variance 
of  opinion  exists  as  to  the  relative  deflection  of  bridges,  produced  by  stationary 
and  by  moving  loads.  Neither  experiment  nor  theory  has  exactly  settled  the 
point. 

Experiments  upon  the  Elwell  bridge,  (Epsom  and  Croydon  Railway,  Eng 
land). 

Velocity  in  feet  per  second.  Deflection  in  inches. 

0  0.215 

25  0.215 

31  0.230 

32  0.225 
54  0.245 
75  0.235 

The  bridge  being  a  cast-iron  girder  of  forty-eight  feet  span,  load  thirty-nine 
tons. 


WOODEN  BRIDGES.  191 

Experiments  on  the  Godstone  bridge,  (S.  E.  R.  R.  England). 
Velocity  in  feet  per  second.  Deflection  in  inches. 

0  0.19 

22  0.23 

40  0.22 

73  0.25 

Cast-iron  girder,  thirty  feet  span,  load  thirty-three  tons. 

Mr.  W.  H.  Barlow,  (Eng.)  observed,  "that  in  case  of  a  timber  viaduct,  a 
freight  train,  at  a  low  speed,  produced  a  certain  deflection  ;  but  an  extra  train, 
with  a  much  lighter  engine,  seemed  to  push  the  bridge  like  a  wave  before  it." 

The  Britannia  tubular  bridge  was  depressed  three  fourths  of  an  inch  by  two 
locomotives  and  a  train  of  two  hundred  and  eighty  tons  standing  still ;  but  at 
seventy  miles  per  hour,  the  deflection  was  sensibly  less. 


CHAPTER    IX 


IRON   BRIDGES. 


"  A  little  knowledge  is  a  dangerous  thing/' 


213.  WITHIN  the  past  ten  years  iron  has  been  brought 
extensively  into  use  for  railroad  bridging;  and  when  em 
ployed  by  those  who  understand  its  chemical  and  mechani 
cal  nature  is  unequalled  for  strength,  durability,  and  ele 
gance  of  appearance ;  but  when,  as  is  too  often  the  case  in 
America,  it  is  intrusted  to  men  who  neither  know  nor  care 
for  any  thing  but  the  price  they  get  for  it,  nothing  can  be 
more  unsafe.     No  material  requires  so  complete  a  knowl 
edge  of  its  properties,  to  be  safely  used,  as  cast-iron. 

NATURE   AND    STRENGTH   OF   IRON. 

214.  The  table  below  shows  the  properties  of  the  several 
descriptions  of  iron  used  in  engineering. 


IRON  BRIDGES. 


193 


Wrought  Iron. 

Cast-Iron. 

Iron  Wire. 

Boiler  Plate. 

Designation  of  the 
quality. 

Weight  per  cubic  foot 

480 

450 

_____ 

480 

in  Ibs. 

Resistance  to  extension 

15000 

4500 

25000 

12740 

in  Ibs.  per  sq.  inch. 

11000 

25000 



7500 

Resistance  to  compres 
sion  in  Ibs.  per  sq.  in. 

.0000066 

.00000608 

.00000675 

.0000066 

Expansion    per  degree 
Farenheitin  lengths. 

.0000000424 

.000000106 

.0000000446 

.0000000524 

Extension  per  Ib.  per 
square  inch. 

.000000149 

.000000083 



.000000189 

Compression  per  Ib.  per 
square  inch. 

90  to  66 

20  to  111 



127  to  75 

Ratio  of  extensive   to 
compressive  strength. 

12500 

17500 





Resistance  to  detrusion, 
or  straining. 

KK 

01 

Relative     transverse 

9«9 

0  1 

strength. 

Column  four  refers  to  boiler  plate  when  built  into  tubes. 

After  wrought  iron  has  become  a  little  compressed,  its 
power  to  resist  a  crushing  force  is  very  much  increased. 

215.  The  tenacity  of  wrought  iron  is  increased  by  heat 
ing.  Experiments  upon  thirty  varieties  gave  the  following 
mean  result,  the  temperature  ranging  from  500°  to  700° 
Fahrenheit. 

Strength  when 


Cold. 

60,000 


Hot. 

64,000 


Cooled. 

70,000 


216.  Stirling's  process  of  toughening  cast-iron,  by  the 
addition  of  malleable  scrap,  increases  the  strength  in  the 
following  ratio :  — 

The  mean  tensile  strength  of  cast-iron  being      15,000  Ibs. 
And  the  compressive  strength  being  .         75,000   " 

When  Stirling-toughened  the  tensile  strength  is  23,000   " 
And  the  compressive  strength  .         .       130,000   " 

The  strength  of  cast-iron  increases  rapidly  up  to  the 
twelfth  or  fifteenth  recasting,  when  it  is  nearly  doubled; 
after  the  fifteenth  melting  the  strength  decreases. 

17 


194  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

217.  Wrought  iron  exposed  for  some  time  to  vibration, 
as  in  the  case  of  railroad   axles,  or  iron  which  has  been 
wrought  with  light  hammers,  loses  its  toughness  and  be 
comes  "  short,"  (crystalline).     The  fibre  may  be  restored  in 
such  cases  by  reheating  and  cooling  slowly. 

218.  GENERAL   RATIOS    OF   THE   STRENGTH   OF   IRON. 

Tension.  Compression.  Cross  Strain. 

Cast,  300  1,666  31.68 

Wrought,      1,000  733  55.40 

I 

OF   THE   STRENGTH    OF   BOILER   PLATES. 

219.  The  strength  of  rolled  boiler  plates  is  no  greater  in 
the  direction  of  the  fibres  than  crosswise,  but  is  more  regular ; 
whence  the  length  of  the  fibre  must  be  placed  as  nearly  as 
possible  with  the  direction  of  the  force. 

A  mean  of  twelve  experiments,  by  Mr.  Fairbairn,  gives 
the  tensile  strength  of  wrought  iron  plates  as  50,960  Ibs. 
per  square  inch;  and  the  compressive  strength  of  plates, 
when  built  into  tubes,  as  30,464  Ibs.,  or  for  safe  use  in  prac 
tice,  for  extension,  12,740  Ibs.,  and  for  compression,  7,500 
Ibs.  In  the  remarks  upon  girder  bridges  the  matter  of  rivet 
ing  will  be  considered. 

CLASSIFICATION  OF  IRON  BRIDGES. 

220.  Iron  bridges  may  be  classified  as  follows :  — 

Those  entirely  of  cast-iron,  or  Arch  and  Girder  bridge. 
Those  of  wrought  iron  alone,  or  Tubular  and  Girder. 
Those  of  iron  wire,  or  Suspension  bridges. 
Those  of  cast  and  wrought  iron,  or  Trussed  bridges. 

The  order  in  which  these  bridges  may  be  placed  as  regards 


IRON  BRIDGES.  195 

cost  of  construction,  and  extent  of  application,  is  as  fol 
lows  :  — 

Number.  Span.  Description  of  bridge. 

1  10  to       50  feet         Cast-iron  girder. 

2  50  to     200     "  Cast  and  wrought  combinations. 

3  200  to  2000     "  Suspension. 

4  200  to     500     "  Cast  arch. 

5  25  to     100     «  Boiler  plate  girder. 

6  100  to     500     "          Tubular. 

Numbers  2,  3,  and  5,  are  the  forms  which  are  in  use  upon 
American  roa'ds.  No.  1,  is  very  liable  to  failure,  requires 
much  more  knowledge  and  care  in  building,  and  is  far  more 
expensive  than  a  wooden  truss,  or  trussed  girder.  No.  4,  is 
very  expensive,  and  causes  a  greater  obstruction  to  the  water 
way  than  any  other.  The  enormous  expense  of  No.  6, 
should,  and  will  prevent  its  adoption  in  the  United  States. 
Let  us  look  at  the  principles  of  construction  of  numbers  2, 
3,  and  5. 

COMBINATIONS    OP    CAST   AND    WROUGHT   IRON. 

221.  Under  this  head  come  all  of  the  iron  trussed  frames 
used  in  this  country. 

As  before  observed,  skill  in  bridge  construction  consists 
in  using  always  that  material  which  with  the  least  expense 
is  the  best  able  to  resist  the  particular  strain  to  which  it  may 
be  exposed.  Thus  wrought  iron  must  always  be  used  to 
resist  tension,  and  cast-iron  compression.  Posts,  braces, 
and  upper  chords  should  always  be  cast,  while  ties  and  lower 
chords  should  be  made  of  wrought  iron. 

The  strength  of  a  railroad  bridge  must  be  such  as  to  resist 
all  extra  shocks  and  strains,  such  as  are  produced  by  derail 
ment  of  engines,  and  breakage  of  axles ;  also  incidental 


196  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

strains  arising  from  change  of  form  by  expansion  and  con- 
Hg  101  traction  of  the  metal,  and 

from  high  winds  and  gales. 
Every  part  of  a  bridge 
not  resisting  some  force  is 
worse  than  useless,  as  it 
adds  to  the  weight.  Light 
ness  not  only  increases 
the  economy  directly,  but 
indirectly  by  removing  a 
part  of  the  permanent 
load. 

222.  Foremost  in  class 
number  two  stands  Wen- 
del  Bollman's  Iron  Sus 
pension  and  trussed  bridge. 
For  simplicity  of  construc 
tion  and  directness  of 
action,  this  bridge  is  un 
surpassed.  The  weight  at 
each  post  is  transferred  at 
once  to  the  abutment  or 
pier.  The  upper  chord  is 
of  cast  iron,  hollow,  octag 
onal  without,  and  circular 
within.  The  posts  consist 
of  an  H  casting,  the  cen 
tral  web  cast  open  and  the 
flanges  whole.  The  top 
is  adjusted  to  the  chord, 
and  the  bottom  to  the 
tension  or  suspending 
rods.  These  latter  are  of 
wrought  iron,  rectangular 


IRON  BRIDGES.  197 

in  section,  joined  when  the  length  requires  it  by  an  eye  bolt. 
Each  set  after  leaving  the  foot  of  the  post,  passes  through 
the  chair  at  A  B,  fig.  101,  and  is  secured  by  a  nut.  The 
junction  of  the  tension  rod  A  C,  and  the  counter  rod 
B  C,  is  attached  indirectly  to  the  foot  of  the  post  by  a  pen 
dulum  or  link ;  which  serves  to  equalize  the  effect  of  expan 
sion  upon  the  rods.  Vibration  and  reaction  are  prevented 
by  the  panel  diagonal  ties  D  H,  and  C  E.  The  floor  is  sup 
ported  by  flanges  at  the  foot  of  each  post.  The  lateral 
bracing  consists  of  a  system  of  hollow  cast-iron  posts,  and 
of  wrought  diagonal  tie  rods.  A  lower  chord  is  plainly  un 
necessary,  its  place  being  taken  by  the  rods  C  B,  F  B,  F  A, 
GA. 

A  bridge  of  this  description  upon  the  Baltimore  and  Ohio 
Railroad  of  the  following  dimensions, 

Clear  span,  .  .        i,nn  <  r.^  r  £•••.»!     •  124  feet 

Length  of  top  chord, 128    " 

Length  of  panel,  .      ;  •-  ^uftff  '< 'ii\ift\&  ^<5  <  1**     " 

Height  of  truss,       .         .     r.  -.,'  v^lf;,^?.,^   *  17     " 

Width,  .  .       ;  ";„"!.  '.-'?,'•, '   ^ .  '/,  '.;;r  .     "          16      « 

Lbs.  of  cast-iron,     .  .        .,  r      f  .      *.        .  65,137 

Lbs.  of  wrought  iron,  .         •        ,         .  33,527 

Whole  weight,          .  .        Y  ,, ^  v'1    '.    '  *  V  98,664 
Weight  per  lineal  foot,       "'*-'"  ]' Y"     $'*: ^  "'  796 

was  subjected  to  the  following  tests. 

Three  locomotives  with  tenders  attached,  and  weighing 
in  all  one  hundred  and  twenty-two  tons,  (nearly  one  ton 
per  foot,)  were  run  over  the  bridge  at  eight  miles  per  hour, 
when  the  deflection  at  centre  was  one  and  three  eighths 
inches,  and  at  the  first  post  nine  sixteenths  of  an  inch.  The 
following  tests  were  applied  to  a  bridge  of  seventy-six  feet 
span  upon  the  Washington  branch  of  the  same  road  : 

An  engine  and  tender  weighing  forty  tons,  caused  a  de- 

17* 


198  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

flection  of  five  eighths  of  an  inch.  A  fast  passenger  train 
deflected  the  bridge  nine  sixteenths  of  an  inch. 

Two  engines  and  tenders,  back  to  back,  at  rest,  and  weigh 
ing  in  all  77J  tons,  caused  a  deflection  of  |£  inch, 
The  same  at  ten  miles  per  hour,  |§     " 
Engines  bead  to  head  at  four  miles  per  hour,                         jf     " 
at  eight  miles  per  hour,                        ||     " 
at  twenty  miles  per  hour,  ££     " 

The  extreme  expansion  of  the  one  hundred  and  twenty-eight 
feet  chord  from  heat,  was  five  sixteenths  of  an  inch  at  each 
end,  or  five  eighths  of  an  inch  in  all,  or  ^3VT  th  of  the  length  ; 
and  that  without  the  slightest  derangement  of  masonry. 
The  rod  C  B,  being  five  times  as  long  as  C  A,  expands  five 
times  as  much,  but  at  the  same  time  the  lengths  D  A,  D  B, 
being  so  nearly  proportional  to  C  A,  and  C  B,  expand  also 
in  the  ratio  of  one  to  five ;  and  thus  no  bad  result  is  experi 
enced. 

The  estimate  of  strains  upon  this  bridge  is  extremely  sim 
ple  ;  the  whole  consisting  of  as  many  separate  systems  as 
there  are  posts.  Each  set  of  rods  sustain  a  rectangle  equal 
to  one  panel,  i.  e.,  the  two  adjacent  half  panels.  Thus  A  C, 
and  C  B,  support  the  rectangle  mm^mm^  the  rods  A  F,  F  B, 
the  rectangle  nn,nn.  Allowance  must  of  course  be  made 
for  the  inclination  of  the  rods.  The  dimensions  of  the  cen 
tral  pair  will  of  course  be  the  same ;  but  those  of  the  other 
sets  will  vary.  The  diagonals  D  H,  and  H  L,  prevent  reac 
tion  ;  and  must  be  able  to  resist  the  action  produced  by  the 
variable  load  upon  one  panel  (as  noticed  in  Chapter  VIII). 

Any  load,  one  at  C  D  for  example,  gives  to  the  posts  a 
tendency  to  revolve  on  A,  as  a  centre  towards  the  abutment ; 
to  oppose  which,  there  must  be  a  force  in  the  opposite 
direction.  The  most  proper  direction  in  which  to  resist 
such  motion  is  the  line  C  K,  i.  e.,  the  line  of  the  lower  chord. 


IRON  BRIDGES.  199 

In  this  bridge  there  is  no  lower  chord,  but  in  place  of  such 
are  put  the  rods  A  G,  A  K,  B  H,  and  B  C  ;  which  prevent 
the  change  of  form  (by  the  motion  of  the  triangle)  and  act 
against  the  upper  chord. 

As  an  example  of  the  estimate  of  strains  upon  this  bridge 
take  the  following. 

Span,  ........         90  feet. 

Rise,        .........     18    " 

Panel,          ........         15     " 

Weight  per  lineal  foot,     .....         2,500  Ibs. 

Whole  weight,      ......         225,000    " 

Weight  on  each  side  truss,         ....    112,500     " 

Weight  on  each  post,    .....  18,750    " 

The  weight  borne  by  each  system,  i.  e.,  one  post  and  the 
two  supporting  rods,  is  18,750  Ibs.  The  strain  to  be  resisted 
by  any  one  rod  depends  upon  its  inclination. 

The  following  figures  show  the  elements  of  the  truss  in 
question  :  — 


=  90.0 


CD  =  18.0 

—          = 

lo 


23  4 
A  C  =  23.4  18750  —  3125  =  15625  which  by  -r^-  =  20132 


=9375       „  =  25260    lf 


Column  1,  gives  the  name  of  the  rod  ;  col.  2,  the  calcu 
lated  diagonal  length  ;  col.  4,  the  applied  weight,  (the  vary- 


200  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

ing  weight  by  reason  of  the  varying  inclination)  found  by 
multiplying  the  whole  weight  upon  one  panel  or  post  by  the 
distance  of  that  post  from  the  abutment,  and  dividing  the 
product  by  the  span.  (Thus  the  load  applied  to  A  C  is 


s     > 

that  on  A  R  is 

Wx  BX 


and  so  on.)  Col.  6,  shows  the  increase  found  by  col.  5  on 
account  of  inclination  as  noticed  in  Chap.  VIII.  ;  and  finally, 
col.  4  gives  the  necessary  sectional  area  of  the  bars  or  rods. 
The  compression  on  the  top  chord  is  evidently  the  sum 
of  the  compressions  of  the  separate  systems  ;  the  compres 
sion  from  any  one  system  is  as  follows,  fig.  102. 

Fig.  102. 


Let  a  d,  c  d  be  the  rods,  and  a  b  c  the  chord ;  also  b  d,  the 
post;  now  if  db  represents  the  weight,  eh  shows  the  ten 
sion  on  a  lower,  or  the  compression  on  an  upper  chord ;  the 
triangles  a  c  d  and  a  b  e  are  similar ;  as  also  ebh  and  d  b  c ; 
whence 

ac      ' 

and 

c  I  X  be 
eh=  — -j compression. 

Numerically  we  have  the  following  figures :  — 


IRON   BRIDGES.  201 

In  the  first  system, 


,         15X77.6 
be=: ~ 


also 


In  the  second  system, 

_  30X62.6 

also 

60X20 

In  the  third  system, 

_  45  X  48.5 
be—       90~ 
also 


that  is,  the  compression  from  the  system  A  C  B,  is  to  the 
weight  on  the  post,  as  twelve  is  to  the  length  of  the  post ; 
or  actually 

18  to  12  as  18,750  to  compression ; 
whence 

18750X12      10_A. 
compression  = ^ or  12500 

in  system  one,  and  in  the  second  system 

18  to  20  as  18750  to  20833. 
In  the  central  system, 

18  to  23  as  18750  to  24000. 

Doubling  the  sum  of  the  first  and  second  systems,  and 
adding  thereto  the  central,  we  have 

2  (12500 +  20833) +24000  =  90666  Ibs., 

as  the  whole  compression  upon  one  side  of  the  bridge. 
As  to  compression  only,  this  would  require  a  section  of 


202  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

about  four  square  inches  of  cast-iron,  which  may  be  obtained 
by  a  tube  of  four  and  one  half  inches  inside,  and  five  inches 
outside  diameter.  We  may  however  need  to  increase  this 
amount  to  resist  flexure,  or  transverse  strains;  in  which 
case  the  length  of  tube  in  one  panel  is  to  be  regarded  as  the 
height  of  a  post,  or  the  length  of  a  beam ;  and  the  size  will 
be  found  by  the  table  on  page  193. 

Each  post  must  bear  18,750  Jbs.,  and  these  being  of  cast 
iron,  to  resist  flexure,  by  the  same  table  above  referred  to, 
should,  if  made  as  a  hollow  cylinder,  be  a  little  over  four 
inches  in  diameter,  and  one  half  inch  thick ;  and  if  of  -|-  or 
H  section,  should  have  a  square  of  nearly  five  inches. 

The  flooring  will  be  dimensioned  by  the  rules  given  in 
Chapter  VIII.  for  single  beams. 

There  is  nothing  about  this  bridge  to  burn,  in  case  of  fire, 
except  the  floor ;  and  that  might  easily  be  made  of  iron. 

To  use  the  words  of  the  inventor,  "  The  permanent  prin 
ciple  in  bridge  building  sustained  throughout  this  mode  of 
structure,  and  in  which  there  is  such  gain  in  competition  with 
any  other,  namely,  the  direct  transfer  of  weight  to  the  abut 
ment,  renders  the  calculation  simple,  the  expense  certain, 
and  facilitates  the  erection  of  secure,  economical,  and 
durable  structures." 

WHIPPLE'S  IRON  BRIDGES. 

223.  The  bridges  built  by  the  above-named  engineer  are  in 
all  respects  well  proportioned,  rigid,  safe,  and  durable.  Cast- 
iron  is  used  as  a  top  chord,  and  wrought  iron  is  employed 
to  resist  the  tensile  forces.  The  plan  put  up  upon  the  New 
York  and  Erie  Railroad,  consists  of  a  hollow  cast-iron  top 
chord,  circular  in  section.  Lower  chords  of  wrought  iron 
rods.  Posts  cast  cruciform  in  section.  Diagonal  tension- 
rods,  as  in  Pratt's  bridge,  (Chapter  VIII.)  The  whole 


IRON  BRIDGES.  203 

structure  is  in  iron  exactly  what  the  above-named  bridges 
are  in  wood ;  and  the  method  of  calculation  is  the  same.  For 
spans  not  exceeding  one  hundred  feet,  this  form  answers 
every  purpose  as  a  railroad  bridge.  It  is  open  to  the  same 
objection  in  larger  spans  as  are  all  trusses  transferring  the 
load  by  a  series  of  triangles  through  which  the  weight  passes 
successively,  namely,  the  effect  of  an  enormous  pressure  at 
the  feet  of  the  second  and  third  pairs  of  braces,  which  should 
be  taken  up  by  arch  braces,  as  in  fig.  69 ;  or  by  rods  from 
the  top  of  the  abutment  pillars  to  the  feet  of  the  second  and 
third  sets  of  posts. 

A  span  of  this  plan,  upon  the  New  York  and  Erie  Rail 
road,  of  forty  feet,  and  which  weighed  only  three  tons,  sup 
ported  a  load  of  fifteen  hundred  pounds  per  lineal  foot  for 
two  days ;  when  the  bridge  had  settled  nearly  one  half  inch. 
A  load  of  rails  weighing  1318  Ibs.  per  foot  (of  bridge)  was 
then  rolled  over,  upon  a  truck  without  springs,  thus  making 
the  whole  load  upwards  of  2,800  Ibs.  per  foot,  when  the 
whole  deflection  was  three  fourths  of  an  inch.  Upon  re 
moving  the  load  the  bridge  returned  to  its  original  position, 
within  one  fourth  of  an  inch. 

SUSPENSION  BRIDGES. 

224.  Suspension  bridges  of  large  span  have  been  generally 
considered  as  entirely  unfit  for  railroad  purposes ;  but  John 
A.  Roebling  has  proved  the  contrary  by  erecting  a  wire  sus 
pension  railroad  bridge  of  eight  hundred  feet  clear  span 
across  Niagara  River ;  which  with  heavy  loads  and  violent 
gales  has  shown  itself  to  be  both  stiff  and  strong  to  any 
desired  amount.  The  construction  of  a  bridge  upon  any 
other  plan  would  have  been  hardly  possible  at  the  site  of 
Mr.  Roebling's  Niagara  bridge,  there  being  no  opportunity 
for  scaffolding  or  for  piers,  pontoons  or  hydraulic  presses. 


204  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

The  simple  road-way  supported  by  cables,  possesses  great 
strength  with  very  little  stiffness.  It  must  be  accompanied 
by  stays  and  trusses  to  check  vibration. 

No  bridge  involves  more  simple  calculations,  and  in  none 
can  we  proceed  with  more  absolute  safety,  than  in  the  wire 
suspension.  European  suspension  bridges  are  generally 
formed  of  cables  made  by  linking  bars  of  wrought  iron 
together.  This  method  is  more  expensive  and  more  liable 
to  failure  than  the  American  plan  of  forming  cables  of  iron 
wire.  An  apparently  good  bar  may  be  defective  inside, 
while  we  are  sure  of  every  component  fibre  of  the  cable ; 
indeed  it  is  very  little  trouble  to  test  each  wire  as  it  is  laid 
into  the  cable. 

The  parts  to  be  considered  in  proportioning  a  suspension 

bridge  are 

The  anchoring  masonry, 

The  anchor  chains, 
The  towers  and  plate, 
The  suspension  cables, 
The  suspending  rods, 
The  stiffening  arrangement, 
The  road-way. 

The  data   given   in   the  construction  of  a  bridge  of  this 
description  are 

The  span, 

The  load  to  be  supported. 


The  assumed  data 


The  varied  line  of  the  cable, 
The  width. 


And  the  required  elements 


The  length  of  cable, 
Lengths  of  suspending  rods, 


IKON  BRIDGES.  205 

Angle  of  tangent  of  cable  at  point  of  suspension 

with  axis  of  tower, 
Tension  upon  the  cables, 
Section  of  the  anchor  irons, 
Amount  of  anchoring  masonry, 
Size  of  the  towers, 
Dimensions  of  trussing  and  of  road-way. 

OF    THE    CABLES. 

225.  The  curve  formed  by  the  cable  of  a  suspension 
bridge  lies  between  the  parabola  and  the  catenary.  When 
loaded  the  curve  is  nearly  the  former,  and  when  unloaded 
the  latter. 

Problem  1. 

Given  the  horizontal  distance  between  the  points  of  sus 
pension  and  the  versed-sine,  to  find  the  length  of  the  cable 
fig.  103. 

Fig.  103. 


Represent  C  E  by  &,  and  E  F  by  a,  and  the  length  of  the 
semicurve  is 

2  /a 


-='[•+101 


18 


206 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Let  the  half  span  be  five  hundred  feet,  and  the  versed- 
sine  or  deflection  eighty  feet,  the  formula  becomes 

L  —  500  \1  + 1  /^.Vlrrz  500X1-0171  =  508.55  feet, 

O  \Ov/U/ 

which  is  the  half  length  of  cables  between  towers. 

Problem  2. 

226.  To  find  the  length  of  the  suspending  rods.  Call 
ing  E  the  horizontal  distance  between  the  vertical  suspend 
ers,  we  have  the  formula 

T2 


in  which  we  place  E,  2  E,  3  E,  etc.,  in  place  of  Y,  thus  call 
ing  the  rods  one  hundred  feet  apart,  we  have 


Centre. 

Rodl. 

Rod  2. 

Rod  3. 

Rod  4. 

Rod  5. 

E* 

4E* 

9£2 

16£2 

25£* 

0 
0 

1002 
5003  X80 
3.20 

200  2 
50PX8° 
12.80 

300  2 

500-*X8° 
28.80 

400  2 
50PX8° 
51.20 

500  2 
X  80 
500  2 

80.00 

Problem  3. 

227.  To  find  the  angle  E  C  G,  fig.  103.  The  formula  for 
the  angle  between  the  axis  of  the  tower,  and  the  tangent  to 
the  curve  of  the  cable  at  the  point  of  suspension  is 

2« 
tang  a  =  ECG=-T-. 

Span  being  one  thousand  feet,  b  is  five  hundred ;  and  a 
.being  eighty  feet,  we  have 


IRON  BRIDGES.  207 

1  />/\ 

tang ECGr=— -  =  log  160  — log  500: 
ouu 

or  2.204120  —  2.698970  =  tang  9.505150  =  17°  45'  =  E  C  G. 
Also,  90°  —  17°  45'  =  72°  15'  =  angle  GCA,  or  ACH. 

When  the  points  of  suspension  are  not  at  the  same  eleva 
tion,  we  proceed  in  the  same  manner :  only  using  F  G,  G  E, 
in  place  of  E  F,  E  C,  in  fig.  103  A. 

Fig.  103  A. 


That  the  resultant  of  the  forces  acting  upon  the  top  of 
the  tower  may  be  vertical,  the  angles  GCA,  and  ACH, 
fig.  103,  must  be  equal ;  if  not,  the  masonry  must  be  so 
arranged  as  to  cause  the  resultant  to  pass  through  the 
centre  of  gravity.  When  more  than  one  span  is  used,  and 
the  openings  are  unequal,  that  the  intermediate  pier  or  piers 
shall  not  be  pulled  over,  the  cable  of  the  largest,  and  con 
sequently  heaviest  span,  must  have  a  greater  inclination 
from  the  horizontal  than  that  of  the  shorter  span;  the 
product  of  the  tensions  by  their  respective  inclinations 
must  be  equal.  Mr.  Roebling's  plan  in  connecting  several 
spans,  is  to  attach  the  cables  of  adjacent  spans  to  a  pendu- 


208  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

him  upon  the  pier,  by  which  arrangement  the  difference  in 
tension  upon  the  different  cables  swings  the  pendulums, 
without  racking  the  masonry. 

Problem  4. 

228.  Given  the  weight  per  foot  of  bridge  and  load,  to  find 
the  tension  at  the  lowest  point  of  the  curve.  The  formula  for 
the  minimum  tension,  that  at  the  vertex  F  of  the  curve,  is 


where  p  is  the  weight  per  foot  of  bridge  and  load,  h  the 
half  distance  between  the  points  of  suspension,  and  /  the 
versed-sine.  Thus  the  span  being  one  thousand  feet,  the 
versed-sine  eighty  feet,  and  the  load  per  lineal  foot  six  thou 
sand  Ibs.,  the  formula  becomes 
6000X000  2 


160 

The  maximum  tension  is  at  the  points  of  support,  and  is 
expressed  by  the  formula 


which,  in  the  case  before  us,  becomes 

6000  X  500  r  11 

T=  --  ^—       5002  +  4X  80  2  2  =  4395  tons. 

229.  The  object  of  the  anchoring  is  to  connect  the  cable 
with  a  resistance  upon  the  land  side,  which  shall  more  than 
balance  the  weight  and  momentum  of  the  bridge  and  load 
upon  the  opposite  side.  The  anchoring  of  the  Niagara 
bridge  consists  of  an  iron  chain  made  of  flat  links,  7  feet 
long,  7  inches  wide,  and  1.4  inches  thick  ;  the  chain  links 
consist  alternately  of  six  and  of  seven  of  these  bars  ;  see 
fig.  104. 


IRON  BRIDGES. 
Fig.  104. 


209 


In  the  Fribourg  bridge  (Switzerland)  the  anchorage  is 
made  as  in  fig.  105,  (see  p.  220,)  by  a  cable  in  place  of  the 
chain.  In  M.  Navier's  suspension  bridge  at  Paris,  over  the 
Seine,  the  anchorage  depended  somewhat  upon  the  natural 
cohesion  of  the  earth  forming  the  bank  of  the  river,  and  this 
being  destroyed  by  the  bursting  of  a  water-pipe  in  the 
vicinity,  the  bridge  fell.  When  there  is  no  natural  rock  for 
an  anchorage,  the  masonry  of  the  shaft  must,  by  its  own 
weight,  resist  the  tension. 

230.  The  height  of  the  towers  must  be  at  least  as  much 
as  the  versed-sine  of  the  cable.  Their  duty  is  to  support 
the  whole  bridge  and  load.  The  breadth  and  thickness  of 
these  columns  must  be  determined  more  with  a  view  to 
opposing  lateral,  than  downward  strains.  The  former 
result  from  the  horizontal  vibrations  of  the  bridge  caused 

18* 


210  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

by  the  action  of  the  wind.  Tremor  and  vibration  caused 
by  a  passing  load,  tend  to  pull  the  towers  into  the  river. 
The  section  for  weight  only  might  be  very  small.  From 
the  practice  of  the  best  builders,  a  mean  section  of  one 
fifth  of  the  height  seems  to  give  the  best  results  ;  thus,  if  a 
tower  is  sixty  feet  high,  the  mean  thickness  should  be 
twelve  feet  ;  or  the  top  being  8X8  feet,  the  bottom  should 
be  16  X  16  feet. 

If  the  bridge  is  so  little  braced  laterally  as  to  swing,  a 
dangerous  momentum  will  be  generated  which  would  very 
much  increase  the  strain,  both  upon  the  masonry  and  upon 
the  cables. 

231.  The  object  of  the  stiffening  truss  is  to  transfer  the 
weight  applied  at  any  one  point  over  a  considerable  length, 
and  to  prevent  vibration.  Its  dimensions  should,  therefore, 
be  those  of  the  counterbracing  in  an  ordinary  truss. 

Any  applied  load  produces  a  certain  depression  in  the 
bridge  :  to  use  the  words  of  Mr.  Roebling,  "  every  train  that 
passes  over  the  bridge  causes  an  actual  elongation  of  the 
cables,  and  consequently  produces  a  depression.  If  the 
train  is  long,  and  covers  nearly  the  whole  length  of  the 
bridge,  and  is  uniformly  loaded,  the  depression  will  be  uni 
form.  If  the  train  is  short,  and  covers  only  a  part  of  the 
floor,  the  depression  will  be  less  general  and  more  local; 
and  will  be  the  joint  result  of  an  elongation  of  the  cables, 
and  of  a  disturbance  of  the  equilibrium.  Depressions  will 
be  in  direct  proportion  to  the  loads,  and  indirectly  as  the 
length  of  train."  The  amount  of  depression  depends  on 
the  elongation  of  the  cables  ;  the  elongation  upon  the 
length.  The  depression  is  shown  by  the  formula 

f>- 
J  '~ 


where  /'  is  the  depression,  n  the  weight  producing  it,  p  the 


IRON   BRIDGES.  211 

weight  per  foot  of  bridge  and  load,  and  h  the  half  distance 
between  the  points  of  suspension. 

The  effect  of  heat,  by  expanding  the  cables,  is  also  to 
depress  the  road-way ;  the  amount  being  shown  by  the  ex 
pression 

*     ^ 
tf*' 

where  c  is  the  elongation  of  the  half  length 'of  cable. 

Upon  the  top  of  the  towers  is  placed  a  pair  of  cast-iron 
plates  separated  by  rollers ;  the  upper  plate  (the  saddle)  is 
thus  enabled  to  move  over  the  lower  one  when  pulled 
either  way  by  the  movement  of  the  cables. 

The  length  of  the  half  cable  between  towers  being  gen 
erally  greater  than  the  distance  from  the  top  of  the  tower 
to  the  anchoring,  expands  more,  when  the  saddle  moves 
towards  the  land  side.  The  dimensions  of  these  castings 
must  be  sufficient  to  resist  the  whole  weight  of  bridge  and 
load. 

232.  As  an  example  of  the  preceding  formula,  take  the 
following :  — 

Assume  the  span  as         .....  1,000  feet. 

Height  of  towers 100     " 

Deflection  of  cables 90     " 

Weight  per  foot  (lineal)  of  bridge        .         .  2,500  Ibs. 

Weight  per  foot  (lineal)  of  load      .         .         .  2,000     " 

Whole  weight  per  foot         ....  4,500     " 

Total  weight 4,500,000     « 

CABLES. 

The  formula  for  the  half  length  of  cables  between  tops 
of  towers  is 


212  HANDBOOK   OF  RAILROAD  CONSTRUCTION. 

which  becomes 


which  doubled,  is  1021.38.  To  this  add  double  the  distance 
from  the  top  of  tower  to  the  anchorage,  (see  page  206,) 
which  is  found  as  follows  :  — 


Also,  tang  E  C  G  =  log  2  a  —  log  6,  or  2.255273  —  2.698970  = 
tang  9.556303  of  which  the  angle  is  19°  48'  and  90°  — 19°  48'  is 
70°  12'  =  angle  G  C  A  or  A  C  H. 

The  height  of  the  tower  being  one  hundred  feet,  and  the 
angle  at  the  tower  70°  12',  we  have 

Sin  19°  48'  9,529,864 

Sin  90°  00'  10,000,000 

log  height  (100)  2,000,000 

log  distance  (295.2)  2,470,136 

which  double,  and  we  have  590.4 ;  finally,  add  twice  the 
breadth  of  the  tops  of  the  towers,  and  the  whole  length  of 
cable  is,  from  anchorage  to  anchorage, 

1021.38  +  590.40  +  16  =  1627.78  feet. 

The  formula  for  the  maximum  tension,  (that  at  the  point 
of  suspension,)  is 

r-PjL 


which  becomes 

4500  X  500 


y/250000  +  32400  =  2966  tons. 


Number  10  iron  wire  (20  feet  per  Ib.)  will  support  1,648 
Ibs.  per  strand  ;  this  is  the  ultimate  strength  ;  the  maximum 


IRON   BRIDGES.  213 

load  for  safety  is  400  Ibs.  per  strand;  whence  2,966  tons,  or 
6,642,500  Ibs.  will  require  16,606  strands;  and  if  we  use 
two  cables,  each  must  have  8,303  wires  ;  or  four  cables  of 
4,151  each.  The  permanent  load  on  suspension  bridges 
should  never  be  more  than  one  sixth  of  the  ultimate 
strength  ;  one  eighth  is  a  good  standard.  The  accidental 
load  should  never  exceed  one  fifth  of  the  whole  strength  of 
the  cables.  The  permanent  weight  supported  by  the 
Niagara  bridge  is  only  one  twelfth  of  the  ultimate  strength 
of  the  cables. 

ANCHOR    CHAINS. 

The   maximum   tension  being  6,642,500  Ibs.  the  whole 
section  of  the  four  anchorings  will  need  to  be 

6642500 

-  443  inches, 


or  111  square  inches  for  each  shaft;  which  is  obtained  by 
eleven  links  ten  inches  wide  and  one  inch  thick.  If  we  so 
attach  the  anchor  chains  to  the  masonry  as  to  reduce  the 
tension  one  fourth  at  the  first  arch,  (see  Fribourg  anchoring,) 
we  may  fasten  three  bars  of  the  chain  at  that  point,  and 
descend  from  the  first  to  the  second  arch  with  eight  bars  ; 
and  leaving  two  bars  at  that  point,  proceed  to  the  bottom 
with  the  remaining  six. 

Where  there  is  no  natural  rock  to  build  the  masonry  into 
or  against,  enough  artificial  stone  must  be  put  down  to 
balance  the  bridge  and  load. 

ANCHORING    MASONRY. 

The  entire  weight  of  the  bridge  and  load  being  4,500,000 
Ibs.  and  the  whole  tension,  as  above  found,  6,642,500  Ibs.,  or 
upon  each  tower  1,660,625  Ibs.  ;  this  is  the  tension  tending 
to  draw  the  masonry  out  of  each  shaft.  This  tension  must 


214 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


be  reduced  on  account  of  the  inclination  of  the  pulling 
force.  The  tower  is  one  hundred  feet  high.  The  distance 
on  the  line  of  tension  from  the  top  of  the  tower  to  the 
anchoring,  as  already  found,  is  295.2  feet ;  whence  the 
actual  effort  to  move  the  anchor  masonry,  is  thus, 

295.2  to  100  as  1,660,625  to  the  effort  or  561,527  Ibs.  If  rock 
weighs  160  Ibs.  per  cubic  foot,  this  is  resisted  by  a  cube  of  3,570 
feet,  or  a  mass  10  X  10  X  35.7  feet. 

TOWERS. 

The  height  of  towers  being  one  hundred  feet,  and  the 
mean  thickness  being  one  fifth  of  the  height,  we  have  mean 
section  20  X  20;  or  top  12  X  12,  and  base  28  X  28. 

• 

SUSPENDING    RODS. 

Assuming  the  horizontal  distances  between  the  centres 
of  the  vertical  suspenders  as  five  feet,  their  lengths,  then, 
will  be  found  by  formula 


and  placing  for  Y2  the  distances  5,  10,  15,  20,  etc.,  we  have, 
commencing  at  the  centre, 


Centre. 

5 

10 

15 

20 

25 

0 
0 

5  2 

5b^X9° 
.009 

102 

50PX9° 
.036 

152    X90 

20  2 
500^  X9° 
.144 

25  2 

V  QO 

5002  X0( 
.081 

500'X9C 
.225 

IRON  BRIDGES. 
TABLE  —  Continued. 


215 


Centre. 

30 

35 

40 

45 

50 

d 

0 
0 

302  -oo 

352    *90 

402 

5^X9° 
.576 

452    X90 

502 

5oPx9° 

.900 

d* 

5002X9( 
.360 

500  *X9( 
.490 

500  'X9° 
.729 

b-2  X0! 
I 

and  so  on,  until  we  arrive  at  the  tower.  Whatever  distance 
above  or  below  the  vertex  of  the  curve  the  road-way  is 
placed,  is  of  course  constant,  to  be  added  to  or  taken  from 
the  above  lengths. 

The  manner  of  putting  in  any  camber  is  simple  both  in 
theory  and  practice.  The  strain  upon  the  suspenders  is 
merely  the  direct  weight  of  the  road-way  and  load.  If  this 
is  3,500  Ibs.  per  foot,  the  five  feet  supported  by  two  rods 
(one  each  side)  will  weigh  17,500  Ibs. ;  each  rod  or  wire 
rope  must  hold  8,750  Ibs. ;  this  can  be  done  by  a  section  of 
one  half  inch  area.  For  extra  strains,  however,  on  so  large 
a  span  as  1,000  feet,  one  inch  of  area  is  not  too  large. 

OF    THE    STIFFENING    TOWERS,    GIRDERS,   AND    STAYS. 

The  object  of  the  girders  supporting  the  rails  is  to  diffuse 
the  applied  weight ;  these  girders  may  be  made  of  a  Howe 
truss  four  or  five  feet  deep,  by  trussed  girders,  only  simply 
deep  and  stiffly  framed  track  strings.  They  should  be  able 
to  distribute  the  load  applied  at  one  point  at  least  fifteen  or 
twenty  feet.  The  side  trusses  transfer  to  a  still  greater  ex 
tent  any  applied  load.  Mr.  Roebling  estimates  the  com 
bined  effect  of  trusses  and  girders  in  the  Niagara  bridge  as 
transferring  the  weight  of  a  locomotive  over  a  length  of  two 
hundred  feet.  This  transferring  counteracts  the  local  depres 
sion.  The  Niagara  truss  is  formed  by  a  system  of  vertical 
posts,  five  feet  apart,  and  diagonal  rods  passing  from  the 
top  of  the  first  post  to  the  foot  of  the  fifth ;  the  inclination 


216 


HANDBOOK   OP  RAILROAD   CONSTRUCTION. 


being  45°,  spreads  the  weight  placed  upon  any  one  pair  of 
posts  over   twice   the    height  of  the  truss,  or  about  forty 
Fig.  106.  feet.    As  to  the  actual  dimen 

sions  of  the  girders  support 
ing  the  rails,  if  we  intend 
them  to  spread  an  applied 
weight  over  forty  feet,  they 
must  be  as  stiff  as  a  bridge 
of  forty  feet  span.  And  as 
regards  the  truss,  if  we  would 
effectually  distribute  the  ap 
plied  weight  and  check  vibra 
tion,  the  trussing  should  be 
as  strong  as  the  counterbrac- 
ing  in  a  large  span  upon  the 
ordinary  plans.  The  princi 
ple  of  trussing  a  suspension 
bridge  may  be  thus  explained. 
See  fig.  106.  Suppose  that 
in  place  of  supporting  the 
three  trusses  D  s  w,  s  m  m', 
and  mf  m  d,  upon  piers  at 
w  and  m',  we  suspend  these 
points  from  the  cable  A  c  B. 
The  cable  is  flexible,  and 
when  we  apply  a  load  at  m, 
the  truss  will  assume  the 
position  D  s  c  n  d,  but  be 
tween  D  and  s,  s  and  n,  n 
and  d,  the  truss  will  be  quite 
stiff.  What  we  require,  then, 
is  to  make  the  figure  op  m  m', 
incapable  of  changing  its 
form,  which  is  done  by 
diagonal  bracing. 


IRON   BRIDGES. 


217 


233.  Undoubtedly  the  finest  specimen  of  a  bridge  of  large 
span  upon  the  suspension  principle,  or  indeed  upon  any 
principle,  is  that  built  by  John  A.  Roebling,  across  the 
Niagara  River,  a  short  distance  below  the  falls.  The 
dimensions  below  of  this  admirable  structure  are  from  the 
final  report  of  the  above-named  engineer. 


Length  of  bridge  from  centre  to  centre  of  tower 
Length  of  floor  between  towers      •         •/...•. 
Number  of  wire  cables       .         .    ,  .  . '       . , 
Diameter  of  each          .         .       ^  .         .         . 
Solid  wire  section  of  each  cable          ^       %  • 
Total  section  of  four  cables     .         .      ',""," 
Whole  section  of  lower  links  of  anchor  irons 
Whole  section  of  upper  links  of  anchor  irons 
Ultimate  strength  of  chains       .... 
Whole  number  of  wires  in  cables  .         .  •  . 

Average  strength  of  a  wire     .'.',*;;!»       [•„ •  . 
Ultimate  strength  of  four  cables     .     .  .;:    %;  .; 
Permanent  weight  supported  by  cables      .     ;-  J- 
Resulting  tension        '•   +  • : .     .       ,  r. ,,      . .     ...  , 
Length  of  anchor  chains  .         .      .  .,        .*     \., , 
Length  of  upper  cables         .        ,       ..«.,:- .^.  «• 
Length  of  lower  cables    .         .        v       .        » 
Deflection  of  upper  cables  (mean  temperature) 
Deflection  of  lower  cables  (mean  temperature) 
Number  of  suspenders         .         ,         .         «  ' 
Aggregate  strength  of  suspenders     .         .! 
Number  of  overfloor  stays  .     -'.*.• 
Aggregate  strength  .         .      .'-.      L '.         .. 

Number  of  river  stays         .         ,Y       '<•"-'.  ^ 
Aggregate  strength  .        vi"   • .-/   ^    .   \  .. 

Elevation  of  grade  above  mean  water       '.'.I  ^    j'.[, 
Depth  of  river        .         .         .       ">1      :*  ;     ^ 
Cost  of  the  bridge       .         .       >.:      .^;     .      ;; 

19 


...    821'  4" 
800  ft. 
'  ..          4 
.    '       10" 

.   60.40  sq.  in. 
.     241.60     " 
.      276     « 
372     k< 
11,904  tons. 
14,560 
.     1,648  Ibs. 
12,000  tons. 
.     1,000    « 

rr,       1,810      « 

;.?!^      66  ft. 
1,261   " 
.     1,193   « 
54  " 
64   " 
624 
.  18,720  tons. 

64 
.     1,920  tons. 

56 

.     1,680  tons. 
245  ft. 
200   " 
$400,000. 


218  HANDBOOK   OF  KAILROAD   CONSTRUCTION. 

234.  The  following  items  are  extracted  from  the  report 
above  referred  to :  — 

"  The  trains  of  the  New  York  Central,  and  Canada 
Great  Western  Railroads  have  crossed  regularly  at  the 
rate  of  thirty  trips  per  day  for"  five  months.  (At  present 
over  two  years.) 

"  A  load  of  forty-seven  tons  caused  a  depression  at  the 
centre  of  five  and  a  half  inches. 

"  An  engine  of  twenty-three  tons  weight,  with  four  driv 
ing  wheels,  depressed  the  bridge  at  the  centre  0.3  feet.  The 
depression  immediately  under  the  engine  was  one  inch;  the 
effect  of  which  extended  one  hundred  feet. 

"  The  depression  caused  by  an  engine  and  train  of  cars 
is  so  much  diffused  as  scarcely  to  be  noticed. 

"  A  load  of  three  hundred  and  twenty-six  tons  produced 
a  deflection  of  0.82  feet  only.  The  Conway  tubular  bridge 
deflects  0.25  feet  under  three  hundred  tons ;  the  span  being 
only  one  half  that  of  the  Niagara  bridge. 

"  The  specified  test  for  the  wire  was,  that  a  strand 
stretched  over  two  posts  four  hundred  feet  apart  should  not 
break  at  a  greater  deflection  than  nine  inches ;  also,  that  it 
should  withstand  bending  square  and  rebending  over  a  pair 
of  pliers  without  rupture.  This  test  corresponds  to  a  tensile 
strain  of  90,000  Ibs.  per  square  inch,  or  1,300  Ibs.  per  wire 
of  twenty  feet  per  pound." 

The  wire  is  preserved  from  oxidation  by  coating  with 
linseed  oil  and  paint.  Upon  the  durability  of  wire  cables 
employed  for  suspension  bridges  the  following  fact  came  to 
light :  Upon  taking  down  the  cables  of  the  footbridge,  put 
up  in  1 848,  by  Mr.  Ellet,  the  wire  was  found  so  little  im 
paired  that  Mr.  Roebling  did  not  hesitate  to  work  it  into 
the  new  cables  ;  also,  the  original  oil  was  found  to  be  still 
soft  and  in  good  condition,  having  been  up  six  years. 


IRON  BRIDGES.  219 

That  iron- work  lying  under  ground  has  been  completely 
covered  with  cement  grout,  as  this  fs  found  by  the  above- 
named  engineer  to  be  an  effectual  guard  against  oxidation. 

Engineers  wishing  to  study  the  details  of  the  Niagara 
bridge,  will  find  the  final  report  of  Mr.  Roebling  full  of 
valuable  matter,  both  as  regards  the  making  of  cables, 
anchoring,  stiffening,  and  the  effect  of  passing  trains. 

NOTE.  —  This  engineer  is  at  present  engaged  upon  a  still  greater  work, 
namely,  a  railroad  suspension  bridge  across  Kentucky  River,  of  1,224  feet 
span,  300  feet  above  the  water.  There  is  no  lower  road-way  in  this  bridge,  the 
cross  section  being  a  triangle  base  upwards. 

235.  NOTE.  —  The  Britannia  tubular  bridge,  across  the  Menai  Straits,  is 
doubtless  a  great  work,  and  also  an  enormously  extravagant  one.  If  no  other 
structure  were  possible  it  would  be  admissible  ;  but  it  is  equalled  in  strength  and 
by  far  surpassed  in  economy  by  Mr.  Roebling's  system  of  trussed  suspension 
bridges.  The  cost  of  material  alone  in  one  span  of  the  Britannia  bridge,  of  460 
feet,  exceeds  the  entire  cost  of  the  Niagara  bridge  of  800  feet  span ;  add  to  this 
that  we  are  sure  of  the  strength  of  wire  cables,  but  not  of  tubes,  and  that  the 
800  feet  span  of  the  Niagara  bridge  weighs  only  1,000  tons  in  itself  against  1,400 
in  a  460  feet  span  of  tube,  and  it  will  not  be  difficult  to  prove  the  superiority  of 
the  suspension  over  the  tubular  system  ;  thus, 

A  suspension  bridge  of  800  feet  span  costs  $400,000. 
A  tubular  bridge  of  460  feet  span  costs  $500,000. 

When  we  double  the  linear  dimensions  we  increase  the  weight  by  the  cube; 
and  the  cost  of  a  tube  is  very  nearly  as  the  weight ;  whence  a  tubular  bridge  of 
800  feet  span  will  cost  2  X  2  X  2,  or  eight  times  500,000,  or  $4,000,000  against 
$400,000.  Thus, 

Suspension  400,000  1 

Tubular  4,000,000  10 


220  HANDBOOK  OP  RAILROAD   CONSTRUCTION. 

Fig.  105. 


Fig.  105,  shows  the  anchoring  of  the  Fribourg  bridge. 


IRON   BRIDGES. 


221 


Fig.  107. 


Fig.  108. 


Fig.  107,  the  manner  of  fastening  the  ground  stays  of  the 
Niagara  bridge. 

Fig.  108,  connection  between  cable  and  suspender. 


Fig,  109. 


Fig.  109  A.    * 


Figs.  109,  109  A,  another  method  of  effecting  the  same. 

19* 


222  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Fig.  110.          Fig   111.       Fig.  112. 


Fig.  113. 


Fig.  113,  connection  of 
land  and  water  cables  in 
Fribourg  bridge. 

Figs.  114, 114  A,  fasten 
ing  of  cables  at  G,  (fig. 
105). 


Fig.  110,  floor  beam 
attachment  to  sus 
pender. 

Figs.  Ill,  112,  floor 
beam  attachment  in 
Niagara  bridge. 

Fig.  114. 


Fig.  114  A, 


IRON  BRIDGES.  223 

Fig.  115,  Mr.  Roebling's   pen-  **•  n5- 

dulum   connection  for  the  cables 
of  two  adjacent  spans. 


BOILER  PLATE  BRIDGES. 
Spans  from  25  to  100  feet. 

236.  These  structures  fulfil  every  requirement  of  safe,  du 
rable,  and  rigid  bridges  ;  being  open  however  to  the  contin 
gency  attendant  upon  all  similar  structures  of  wrought  iron, 
namely,  the  becoming  crystalline  when  exposed  to  vibration. 
Time  only  will  show  whether  this  is  a  sufficient  cause  for 
their  non-adoption. 

Each  side  truss  consists  as  it  were  of  a  top  and  bottom 
chord  connected  by  a  vertical  web.  The  whole  being  of 
wrought  iron,  requires  that  the  section  of  the  upper  chord 
should  be  to  that  of  the  lower,  as  ninety  to  sixty-six. 

The  general  plan  of  such  bridges  is  shown  in  fig.  116. 
This  is  the  patent  wrought  iron  girder  bridge  of  Mr.  Fair- 
bairn.  The  upper  chord  is  formed  by  connecting  the  four 
plates  a  a  act,,  by  angle  irons.  The  web  is  formed  either  by 
a  single  or  a  double  plate,  stiffened  laterally  by  T  iron  placed 
at  the  vertical  plate  joints,  as  shown  generally  at  B,  and 
detailed  at  C  and  D ;  or  by  a  pair  of  plates  separated  by  a 
space  as  at  B',  thus  forming  a  rectangular  tube.  The  lower 
chord  is  made  by  bending  horizontally  the  lower  part  of  the 
web,  and  to  the  flanges  thus  formed  riveting  the  plate  m  m. 
The  suspending  rod  //  is  applied  to  the  upper  chord  by  a 
washer  as  at  E. 

The  central  connecting  web,  acting  as  do  the  braces  and 
ties  in  a  wooden  truss,  should  be  more  stiff  at  the  ends  of 


224 


HANDBOOK  OF  RAILROAD    CONSTRUCTION. 


Fig.  116. 


IRON  BRIDGES.  225 

the  span  than  at  the  centre.  This  is  easily  effected  by 
joining  the  web  plates  towards  the  end  by  stronger  T  irons 
than  at  the  centre.  The  joints  for  the  rib,  or  the  vertical 
plates,  either  single  or  double,  are  shown  in  figs.  C  and  D. 

An  example  of  the  need  of  such  increased  stiffness  towards 
the  ends,  was  given  to  the  experimenters  upon  the  Britannia 
model  tube,  which  (tube)  was  found  to  yield  by  buckling 
near  the  ends  of  the  span  sooner  than  elsewhere.  Thus 
advised,  the  vertical  plates  were  made  thicker  as  the  end  of 
the  span  was  approached.  Examination  of  the  principles 
of  proportioning  a  common  wooden  truss  would  have  shown 
this  without  experiment. 

The  tensile  and  compressive  strength  of  rolled  boiler 
plates  (by  the  table  on  page  194,)  is,  extension  12,740  Ibs. 
per  square  inch,  compression  7,500  Ibs.  The  strength  of 
such  work  depends  in  a  very  great  measure  upon  the  size 
and  disposition  of  rivets.  In  plates  exposed  to  compression, 
the  strength  is  not  so  much  affected  by  riveting  as  in  those 
subjected  to  tensile  strains;  as  to  whatever  amount  the 
plate  is  cut  away,  by  the  same  amount  is  the  resistance  to 
tension  reduced. 

237.  Mr.  Fairbairn  found  that  to  obtain  the  maximum 
strength  of  riveted  plates,  the  section  of  the  rivets  should 
equal  that  of  the  plates,  that  is,  in  a  plate  four  inches  wide, 
if  there  are  two  rivets,  the  area  of  each  must  be  one  inch ; 
or  the  diameter  1|  inches;  thus  leaving  a  section  of 

4—  2£=  If  inches, 

which  divided  by  four  gives  seven  sixteenths  of  an  inch  as 
the  distance  from  the  edge  of  the  plate  to  the  side  of  the 
first  rivet ;  and  seven  eighths  of  an  inch  between  rivets.  If 
the  bolt  yields  by  shearing,  the  rim  is  destroyed  by  detrusion, 
or  crushing  across  the  fibres.  That  the  rivets  and  plates 


226  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

may  be  equally  strong,  their  products  of  area  of  section  by 
the  actual  strength  per  unit  of  area  must  be  equal.  The 
detrusive  strength  of  wrought  iron  (see  page  128)  is  12,500 
Ibs.  per  inch,  whence  the  proportion 

12,500  :  15,000  :  :  1  :  d  : 

where  1  is  the  resisting  length  of  the  plate  at  right  angles 
to  tension,  and  d,  the  sum  of  rivet  diameters.  Thus  sup 
pose  we  have  a  plate  13.2  inches  wide,  to  be  fastened  with 
nine  rivets  of  0.8  inch  diameter  ;  we  have 

9X0.8  =  7.2  =  ^, 
and  the  above  proportion  becomes 

15,000  :  12,000  :  :  7.2  to  6  inches, 

which  is  the  length  of  plate  section  at  right  angles  to  ten 
sion.  As  there  are  nine  rivets,  there  will  be  eight  spaces 
between  them,  and  one  space  at  each  edge  of  the  plate,  half 
as  large  as  those  between  ;  or  reducing  all  to  the  same  size, 


2=18; 
and  as  the  whole  plate  section  after  punching  is  six  inches, 

6 
—  =  .33  or  J  inch 

for  the  edge  space,  and  two  thirds  inch  between  rivets. 
Proceeding  thus,  the  result  compares  with  the  practice  of 
Mr.  Fairbairn  as  follows  :  — 

Distance 

Diameter  of  rivet.  between 

rivets. 

Mr.  Fairbairn         f  inch,  or  0.625  inch,         0.8 
Handbook  f  inch,  or  0.666  inch,         0.8 

The  difference  between  the  results,  or  0.041  inch,  less  than 


IRON   BRIDGES.  227 

one  sixteenth  inch,  will  be  partially  absorbed  by  the  remark 
of  Mr.  Fairbairn  that  the  area  of  the  rivet  should  be  nearly 
as  much  as  that  of  the  plate,  and  partly  by  the  difference  in 
results  showing  the  detensional  force  of  iron. 

238.  In  experimenting  to  determine  the  resistance  of  riv 
ets,  Mr.  Fairbairn  found  that  by  the  common  plan  of  riveting, 
fig.     117,    the  ris.117. 

strength  of 
plates  when 
whole,  single, 
and  double  riv 
eted,  was  as 
follows,  the 
section  of  the 
punched  plate 
being  in  each  case  equal  to  that  of  the  whole  one. 

Whole  plate,  .  """.'"  .  .  .  100. 
Single  riveted,  ,_.,  ,.  x  .  .  .  .  56. 
Double  riveted, 70. 

This  loss  of  strength  made  him  fearful  of  the  ability  of  the 
tension  plates  of  the  Britannia  bridge  to  do  their  duty ;  and 
he  was  led  to  adopt  what  he  terms  "  chain  riveting,"  which 
consists  in  placing  the  rivets  as  in  fig.  118,  or  in  the  same 
line  of  tension.  The  strength  «of  plates  thus  made  he  con 
siders  as  great  at  the  joints  as  elsewhere. 

239.  As  to  the  diameter  of  rivets,  we  have  the  following 
results  of  the  practice  of  the  best  English  engineers. 

Thickness  of  plate,    ±,     ^,     f,     ft,    J,     ft,    f,     H>     & 
Diameter  of  rivet,      f,      f,      J,      1,      1,     1J,    !£,    If,    If 

240.  As  to  the  distance  in  the  direction  of  the  force  from 
rivet  to  rivet,  also  from  the  first  rivet  to  the  plate  end,  we 


228  HANDBOOK   OF  KAILROAD   CONSTRUCTION. 

gather  the  following  from  the  best  executed  works  in  boiler 
plate.     See  fig.  118. 

Plates  exposed  to  compression, 

c  b  =  2  diam.,  df=  lj  diam. 
Plates  exposed  to  extension, 

cb  =  2^  diam.,  df=  2  diam. 

the  diameter  being  that  of  the  rivet. 

The  distance  at  right  angles  to  the  force  has  already  been 
given. 

241.  If  we  knew  the  lateral  adhesion  of  rolled  plates,  that 
is,  the  resistance  of  the  fibres  to  sliding  horizontally  past 
each  other ;  we  should  determine  the  distance  of  rivets  in 
the  direction  of  tension  as  follows  :  — 

Let  R,  equal  the  resistance  per  unit  of  area  for  detrusion 
or  shearing,  Rl  the  lateral  adhesion  of  rolled  plates,  and  we 
should  have 

also 
and 


whence 

d'  — 


and  finally 

rf'   iPxrf  A 
d  =*[-3r  ~d\ 


supposing  the  piece  1,2,3,4,  fig.  118,  to  split  out. 

The  diameter  of  the  semi-spherical  head  of  the  rivet  should 
be  three  times  the  thickness  of  the  plate  to  be  riveted  ;  that 


IRON  BRIDGES.  229 

of  the  conical  head  four  times  ;  and  the  height  of  both  of 
the  heads,  once  and  one  half  the  plate  thickness. 

242.  Examples  of  the  application  of  the  preceding 
remarks. 

Suppose  we  wish  to  build  a  boiler  plate  bridge  of  one 
hundred  feet  span,  twelve  feet  rise,  weight  of  bridge  and 
load  3300  Ibs.  per  lineal  foot.  The  tension  by  formula 


W  S' 
=-       (see  Chap.  VIII.) 


becomes 


Each  side  truss  will  bear  one  half  of  this  or  171,875  Ibs.,  and 
as  wrought  iron  resists  eleven  thousand  pounds  of  compres 
sion  per  square  inch,  the  required  section  of  the  top  chord 

will  be 

171875 
nOO(T=:          square  inches. 

Also  the  lower  chord  resisting  fifteen  thousand  pounds  per 
square  inch,  must  have 

171875 

=11.0  square  inches 


of  area  nearly. 

If  we  make  the  tube  at  top  of  one  fourth  inch  iron,  and  8 
X  10  inches  ;  fastening  the  plates  by  one  fourth  inch  angle 
iron,  four  inches  on  the  side,  the  section  becomes 

One  top  plate  10  X  i  =  2|  square  inches. 

One  bottom  plate      10  X  i  =  2  i  " 

Two  side  plates  8  X  i  =  4  " 

Four  angle  irons         £  X  8  =  8  " 

In  all,     17 

In  the  lower  chord,  if  we  bend  the  web  plates  (of  f  inch) 

20 


230  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

so  as  to  form  a  flange  of  eighteen  inches  in  width,  and  to 
that  rivet  a  bottom  plate  18  X  i,  we  shall  have 

In  the  flanges,         .         .         .         18Xf  — 6f 
Bottom  plate,     .         .         .         .     18Xi  =  4J 

In  all,  TlJ 

The  web  acting  as  both  ties  and  braces,  must  be  able  to 
support  the  following  load. 

Whole  weight  of  bridge  and  load  is,  in  round  numbers,  344,000  Ibs. 

One  half, 172,000    « 

And  upon  each  end  of  the  truss,         ....       86,000   " 

to  resist  which,  at  eleven  thousand  pounds  per  square  inch, 
requires  eight  inches  nearly,  regarding  the  plate  as  a  brace. 
Now  the  side  of  the  bridge  being  one  hundred  feet  long, 
and  twelve  feet  wide,  will  contain  any  system  of  bracing 
that  we  choose  to  draw  thereon.  Suppose,  for  example,  that 
we  chalk  a  line  upon  the  erected  bridge  representing  an 
arch-brace,  extending  from  the  end  to  the  centre.  Such  a 
brace  has  actually  existence  in  the  bridge ;  and  the  same 
idea  holds  good  for  any  system  of  braces  that  may  be  as 
sumed.  We  ought,  therefore,  to  take  the  most  disadvan 
tageous  system  that  can  have  place,  and  giving  such  a  good 
bearing  upon  the  abutment,  estimate  its  width  and  thickness. 
Suppose  that  we  draw  a  natural  size  representation  of 
Howe's  bridge,  the  end  braces  must  support  a  load  of 
eighty-six  thousand  pounds,  which  at  eleven  thousand  Ibs. 
per  inch,  requires  a  section  of  nearly  eight  inches ;  and  if 
the  plate  is  one  half  inch  thick,  the  brace  must  be  sixteen 
inches  deep.  The  manner,  however,  in  which  the  plate 
would  yield  is  by  bulging  laterally ;  which  is  to  be  checked 
by  the  before-mentioned  T  connecting  irons  at  the  sides. 
It  may  be  thought  that  the  above  method  of  considering 


IRON  BRIDGES.  231 

the  plates  as  braces,  would  give  very  little  thickness  by 
assuming  very  wide  plates.  The  answer  to  this  is,  that  the 
side  plates  must  not  be  so  thin  as  to  need  more  stiffening 
angle  irons  by  weight,  than  a  thicker  plate  with  less  stiffen 
ing.  Of  course  the  weight  should  be  minimum. 

243.  As  an  actual  example  of  this  plan  we  have  the  fol 
lowing,  built  by  Mr.  Fairbairn  for  the  Blackburn  and  Bolton 
Railroad,  across  the  Leeds  and  Liverpool  Canal. 

Span,  60  feet, 

Length, 66    « 

End  bearings,  each,        ....  3     " 

Rise, 5    u 

Width, 28     " 

for  a  double  track.  Top  chord  of  three  eighths  iron,  web 
of  five  sixteenths,  lower  flange  of  three  eighths,  and  vertical 
web  plates  stiffened  by  T  irons. 

This  bridge  was  tested  as  follows :  — 

Three  engines,  weighing  twenty  tons  each,  running  from 
five  to  twenty-five  miles  per  hour,  deflected  the  bridge  .025 
feet.  Two  wedges,  one  inch  high,  being  placed  upon  the 
rails,  and  the  engines  being  chopped  from  that  height,  the 
bridge  was  deflected  at  the  centre  .035  ft. ;  with  wedges 
of  one  and  one  half  inches  the  deflection  was  .045  ft.  The 
cost  of  this  bridge  (in  England)  was  estimated  by  Mr.  Fair- 
bairn  at  $4,500,  while  that  of  a  cast-iron  bridge  of  the  same 
span  was  $7,150. 

244.  Example  2.  —  Manchester,  Sheffield,  and  Lincoln 
shire  Railroad  (England)  Bridge,  at  Gainsborough,  on  the 
river  Trent.     Two  spans,  each  one  hundred  and  fifty-four 
feet.      Rise  twelve  feet.      Top  chord,   double  rectangular 
tube,  36|  X  16  inches,  vertical  web  as  before,  and  horizontal 
plate  for  the  lower  chord.     The  floor  beams  are  wrought 


232  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

iron  girders,  cruciform  in  section,  ten  inches  wide,  and  one 
foot  three  inches  (15")  deep,  placed  four  feet  apart. 

245.  Example  3. —  Fifty-five  feet  boiler  plate  bridge, 
built  by  James  Millholland,  in  1847,  for  the  Baltimore  and 
Susquehanna  Railroad  Company.  Each  truss  consists  of 
two  vertical  plates  55  X  6  feet,  formed  of  plates  thirty-eight 
inches  wide  by  six  feet  deep,  the  plates  being  fastened  to 
gether  by  bolts  passing  through  cast-iron  sockets.  The 
lower  chord  is  formed  by  riveting  two  bars  5x1  inches 
to  each  side  of  each  truss  plate;  making  in  all  eight. 
Top  chord  —  one  bar  of  the  same  size  on  each  side  of  each 
plate,  compression  being  made  up  by  a  wooden  chord  be 
tween  the  plates.  Height  of  bridge,  six  feet ;  length, 
fifty-five  feet ;  width,  six  feet ;  weight,  fourteen  tons ;  cost, 
$2,200,  or  forty  dollars  per  foot.  The  inventor  thinks  thirty 
dollars  per  foot  enough  when  a  considerable  amount  of  such 
bridging  is  wanted. 

NOTE.  —  White,  buff,  or  some  light  color  should  be  used  in  painting  iron 
bridges,  as  such  throw  off,  and  do  not  absorb  heat  from  the  sun. 


CHAPTER    X, 

STONE   BRIDGES. 


A  COMPLETE  treatise  on  stone  bridging  would  be  of  little 
practical  value  to  the  American  engineer,  and  would  occupy 
too  much  of  the  necessarily  small  space  allowed  here.  The 
object  in  the  present  chapter  is  to  give  the  manner  of  dimen 
sioning  stone  arches  of  from  ten  to  sixty  feet  span,  and  of 
proportioning  retaining  walls,  piers,  and  abutments. 

CONTRACTION  OF  THE  WATER-WAY. 

246.  In  building  a  bridge  across  a  stream,  we  must  be 
careful  not  to  obstruct  the  water-way  so  as  to  prevent  free 
passage  to  the  highest  floods.  Regard  must  be  had  to  this 
in  fixing  the  size  of  the  spans,  and  the  thickness  and  num 
ber  of  the  piers.  By  contracting  the  width  of  the  stream 
the  velocity  is  increased  beneath  the  arches,  the  same 
amount  of  water  being  obliged  to  pass  through  a  smaller 
space,  and  when  the  bottom  is  of  such  a  nature  as  to  yield 
to  this  action,  there  is  danger  of  the  foundation  being  under 
mined.  If  the  form  and  size  of  the  piers  be  so  arranged  as 
not  to  increase  the  velocity,  such  danger  will  be  avoided 
and  floods  will  pass  without  harm.  In  bridges  crossing 

20* 


234  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

navigable  streams,  if  the  bottom  is  not  destroyed  the  velocity 
may  be  made  so  great  as  to  impede  navigation. 

247.  The  following  table  is  from  Gauthey,  Construction 
des  Fonts,  showing  the  velocities  which  are  joint  in  equi 
librium  with  the  material  composing   the  bottom  of  the 
stream. 

State  of  the  water.        Velocity  in  feet  per  second.  Nature  of  bottom. 

Torrents,  10'  0"  Large  rocks. 

Floods,  3'  3"  Loose  rocks. 

Common,  3'  0"  Gravel  and  stones. 

Regular,  2'  0"  Fine  gravel. 

Moderate,  1'  0"  Sand. 

Slow,  0'  6"  Clay. 

Very  slow,  0'  3"  Common  earth. 

248.  If  b  represents  the  width  of  the  natural  water-way  ; 
c,  that  as  reduced  by  the  structure  ;    F,  the  velocity  of  the 
stream  in  the  natural  state  ;  then  the  augmented  velocity 
is  expressed  by 

W—m  V--, 
c 

mbV 
and  c=     yy     ; 

where  m  is  a  constant  quantity  expressing  the  contraction 
which  takes  place  in  passing  the  narrow  place,  which, 
according  to  Du-Buat,  is  1.09;  but  depending  somewhat 
upon  the  form  of  the  bridge  piers  ;  adopting  which  value, 
we  have 

JF:=1.09  F-; 
c 

1.09  bV 


Example.  —  Let  the  bottom  be  gravel,  the  width  of  the 


STONE  BRIDGES.  235 

natural  water-way  one  hundred  feet,  the  velocity  one  foot 
per  second  :  now  for  a  gravel  bottom  the  velocity  must  not 
exceed  two  feet  per  second,  whence 

1.09  X  100  X  1 


which  is  the  width  of  the  contracted  water-way  ;  and 
100  —  54£,  or  45£  feet  may  be  occupied  by  piers  or  other 
obstructions. 

The  amount  of  fall  which  the  water  suffers  in  passing  the 
pier  is  found  by  the  following  formula,  the  notation  being 
the  same, 


Thus  the  velocity  being  one  foot  per  second,  m  being  1.09 
and  b  — 100  ;  also,  c  =  54|,  we  have 


1  XIX  1.09X1.09-  X  100X100  —  54^X541 


The  velocity  of  a  river  is  greatest  at  its  surface  and  at 
the  centre  of  the  stream.  In  the  same  river  the  velocity  is 
nearly  as  the  square  root  of  the  depth;  thus  the  surface 
velocity  being  known,  that  for  any  other  depth  may  be 
easily  found.  The  velocity  of  streams  should  always  be 
noted  at  the  times  of  the  highest  floods.  For  measuring 
the  velocity  of  running  water  a  bottle  enough  filled  with 
water  to  maintain  an  upright  position,  with  a  small  rod 
placed  through  the  stopper  having  a  red  flag  upon  the  upper 
end,  answers  very  well.  Velocities  of  undercurrents  may 
also  be  measured  by  so  loading  the  bottle  as  to  cause.it  to 
float  two,  four,  six,  or  ten  feet  below  the  surface. 


236  HANDBOOK   OP  KAILROAD   CONSTRUCTION. 


OF   THE  FORM  OF  THE  ARCH. 

249.  There  'are  three  general  forms  which  may  be  given 
to  the  intrados  of  a  stone  arch. 

Semicircular,  or  one  hundred  and  eighty  degrees. 
Segmental,  less  than  one  hundred  and  eighty  degrees. 
Basket  handle,  nearly  elliptical,  being  formed   by  a  number  of 
circular  curves. 

Full  centre  (semicircular)  arches  offer  the  advantages  of 
great  solidity  and  care  of  construction ;  but  unless  the 
springing  lines  are  high,  contract  considerably  the  water 
way. 

Segrnental  arches  give  the  freest  passage  to  the  water, 
are  easily  built,  but  throw  a  great  horizontal  strain  upon  the 
abutments. 

The  basket  handle  gives  free  passage  to  the  water,  when 
not  too  flat  are  very  strong,  are  easily  adjustable  to  different 
ratios  between  the  span  and  the  distance  between  grade 
and  the  spring  line,  and  except  making  the  centres,  are 
easily  built.  Whatever  the  form  of  the  arch,  the  line  of 
arch  springing  should  not  be  below  high  water. 

The  manner  of  tracing  the  full  centre  and  segmental 
curves  is  too  simple  to  need  remark. 

250.  In  tracing  the  basket  handle  curve,  the  following 
conditions  must  be  observed  :  — 

The  tangents  at  springing  must  be  vertical. 

The  summit  tangent  must  be  horizontal. 

The  curve  at  springing  must  inclose  the  ellipse. 

The  radius  of  summit  must  not  be  greater  than  the  span. 

The  number  of  arches  composing  the  curve  must  not  be 
less  than  three,  nor  more  than  eleven ;  and  must  be  uneven. 
Perronet's  fine  bridge  of  Neuilly,  over  the  Seine  at  Paris, 


STONE  BRIDGES.  237 

has  eleven  centres.     In  spans  of  sixty  feet  and  under,  it  is 
unnecessary  to  use  more  than  five  centres. 

251.  The  three  Fig.  119. 
centred    curve    is 

described    as    fol 
lows,  fig.  119 :  — 

Let  A  B  repre 
sent  the  span,  and 
c  D  the  rise,  with 
c  as  a  centre  and 
c  A  as  radius,  de 
scribe  the  quad 
rant  A  F  E  ;  make 
the  angle  A  C  F 
60°.  Parallel  to  F  E  draw  D  G,  and  parallel  to  F  C  draw 
G  K.  H  is  the  centre,  and  A  G  the  arc  of  the  springing 
curve  ;  also  GD  is  the  arc,  and  K  the  centre  of  the  summit 
curve. 

s 

THE    FIVE    CENTRED    CURVE. 

252.  The  common  construction  of  the  five  centred  curve 
leaves  the  radii  of  the  extreme  curves  to  be  assumed.     The 
following  method  fixes  all  of  the  dimensions  when  the  span 
and  rise  are  given  :  - — 

Let  c  B  be  half  the  span  and  c  D  the  rise. 
Join  D  B. 

Draw  n  K  through  n  perpendicular  to  D  B. 
Make  B  a  equal  to  c  D, 
Also  c  e  to  c  a. 
Draw  e  Kr  o  and  K  a  m. 

K  H'  and  K'  are  the  centres,  and  H'  m  and  H'  o  the  lines  repre 
senting  the  several  curves. 

For  spans  of  from  twenty-five  to  one  hundred  feet,  the  five 


238  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

centred  arch  answers  every  purpose ;  making  a  strong  and 
well  proportioned  structure. 

THICKNESS   OF  VOUSSOIRS,   (RING  STONES). 

253.  The  thickness  of  the  voussoir,  or  arch  stone,  depends 
upon  the  form  and  size  of  the  arch,  the  nature  of  the  ma 
sonry,  and  the  character  of  the  stone.  No  authority  gives 
more  reliable  results  than  Gauthey,  who,  for  stone  of  aver 
age  quality,  with  hammer  dressed  beds,  laid  in  cement,  gives 
the  following  proportions  between  the  span  and  depth  of 
key :  — 

For  spans  under  six  feet  the  depth  should  be  thirteen  inches. 

From  six  to  fifty  feet,  13  inches  plus  ^  of  the  span. 

From  fiftj  to  one  hundred  feet,  fa  of  the  span. 

For  over  one  hundred  feet,  fa  of  100  plus  •£$  of  the  remainder. 

Thus  for  a  span  of  one  hundred  and  ninety-six  feet  we 
have 

100X12  ,   96X12 
24  ~~48      ' 

or,  50  +  24  equal  in  all  to  seventy -four  inches,  or  six  feet 
and  two  inches ;  wrhence  the  following  table :  — 

Span  of  arch  in  feet.  Thickness  of  voussoir  in  inches. 

6  13  +  0  =  13 

8  13  +  2  =  15 

10  13  +  3  =  16 

12  13  +  3  =  16 

15  13  +  4  =  17 

18  13  +  5  =  18 

20  13  +  6  =  19 

25  13  +  7  =  20 

30  13  +  8  =  21 

35  13  +  9  =  22 


STONE   BRIDGES.  239 

Span  of  arch  in  feet.  Thickness  of  voussoir  in  inches. 

40  13  +  10  =  23 

45  13  +  11  =  24 

50  13  +  13  =  26 
60  =30  inches. 

THICKNESS   AND  FORM  OF  ABUTMENTS. 

254.  The  above  depend  upon  the  span  and  form  of  the 
arch,  the  height  of  the  abutment,  and  character  of  the  ma 
sonry. 

Different  methods  of  determining  the  thickness  of  an 
abutment  have  from  time  to  time  been  given ;  several  very 
correct  rules  have  been  arrived  at,  but  difficult  of  applica 
tion.  The  most  simple  rule  is  given  by  Hutton  in  the 
course  of  mathematics  edited  by  Rutherford ;  it  is  as  fol 
lows  :  — 

Fig.  120. 

Let  A  B,  CD,  fig.   ' 
120,   be   one   half   of 
the  arch,  and  A  G  F 
the  abutment. 

From  the  centre  of 
gravity  K  of  the  arch, 
draw  the  vertical  K  L ; 
then  the  weight  of  the 
arch  in  the  direction 
K  L  will  be  to  the 
horizontal  thrust,  as  K  L  to  LA.  For  the  weight  of  the 
arch  in  the  direction  K  L,  the  horizontal  thrust  L  A,  and 
the  thrust  K  A  will  be  as  the  three  sides  of  the  triangle 
K  L,  LA,  K  A ;  so  that  if  m  denotes  the  weight  of  the 
arch, 

LA 


240  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

will  be  its  force  in  the  direction  L  A,  and 


its  effect  on  the  lever  G  A  to  overturn  the  wall,  or  cause  it 
to  revolve  about  the  point  F. 

Again,  the  weight  or  area  of  the  pier  is  as  E  F  X  F  G, 
and  therefore  E  F  X  F  G  X  i  F  G,  or  J  F  G2  X  E  F,  is  its 
effect  upon  the  lever  i  F  G,  to  resist  an  overthrow.  Now 
that  the  abutment  and  the  arch  shall  be  in  equilibrium  these 
two  effects  '  must  be  equal  to  each  other  ;  whence  we  must 
have 


whence 


The  following  table  has  been  calculated  for  the  use  of 
builders  and  engineers,  giving  the  thickness  of  abutments 
for  different  spans  and  heights. 

255.  THICKNESS    OF   RECTANGULAR   ABUTMENTS. 


span.  5  8  10  15  5           8  10  15 

6  3  3  31  31  31         4           4  5 

8  31  4  41  41  4           41  51  6 

10  4  5  5  5  41        5|         61  7 

15  41  51  51  6  5           61         71  8 

20  5  51  6  7  6           7±  8  9 

25  51  6  6J  7^-  7  7^  8J  9^ 

30  6  7  8  81  8  81  91  10 

35  61  7  81  9  9           9£  10  11 

40  7  71  8J  91  91  10  11  12 

45  71  8J         91  10  10  10  J  111  i2\ 

50  89  10  11  101  Hi.  12£  13 


STONE  BRIDGES. 


241 


256.  The  form  of  a  bridge  abutment  will  depend  upon 
the  localities  and  upon  the  use  to  which  the  oiidge  is 
to  be  put,  whether  used  for  a  railroad,  or  for  common 
travel ;  whether  near  a  large  city,  or  in  a  location  where 
appearance  need  not  be  regarded.  Where  a  river  acts 
dangerously  upon  a  shore,  wing  walls  will  be  necessary. 
These  wings  may  be  curved  or  straight,  and  may  be  simply 
the  abutment  produced,  or  may  be  swung  around  into  the 


Fig.  121  B. 


21 


242  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

bank  at  any  required  angle,  until  the  winged  abutment,  as 
in  figs.  121,  121  A,  121  B,  becomes  the  U  abutment,  fig. 
124 ;  or  by  moving  the  walls,  W  and  W,  parallel  to  them 
selves,  takes  the  form  of  the  T  abutment,  fig.  122. 

Fig.  122. 


The  curved  wing,  in  fig.  121,  being  arched,  requires  a 
Little  less  thickness,  but  at  the  same  time  is  longer.  B  B, 
show  the  bridge  seats,  and  c  e,  the  parapets.  The  slope  of 
the  wings  may  be  battered  with  an  inclined  coping,  or  off- 
setted  at  each  course.  Wing  walls,  subjected  to  special 
strains  or  to  particular  currents  of  water,  require  positions 
and  forms  accordingly.  In  skew  bridges,  as  in  Chap.  V., 
the  wing,  at  the  acute  angle,  is  longer  and  inclines  less  from 
the  face  of  the  abutment  than  that  at  the  obtuse  angle.  The 
more  the  wing  departs  from  the  face  line  and  swings  round 
into  the  slope,  the  greater  the  thrust  becomes  upon  it,  as 


STONE   BRIDGES. 


243 


the  centre  of  pressure  is  raised ; 
imum  when  the 
wing  is  inclined 
from      forty-five 
to    seventy    de 
grees    from    the 
face  of  the  abut 
ment.  The  body 
of    an   embank 
ment,  as  well  as 
any  other  retain 
ing  wall,  may  be 
much      stronger 
by   giving   it    a 
trapezoidal     in 
stead   of  a  rec 
tangular  section, 
as  the  resisting  lev 
erage      is      thereby 
much  increased.    A- 
butments    may    be 
to    advantage    but 
tressed   in  order  to 
resist  special  strains, 
as   in    case   of  the 
arches  or   braces  of 
wooden  bridges. 

257.  Railroad 
abutments  except 
for  a  double  track, 
require  but  little 
breadth  on  top,  ex 
cept  where  the  truss  itself  rests. 


the  thrust  becomes  a  max- 

Fig.  123. 


The  common  T  abutment 


244  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

originated  by  Captain  John  Childe,  and  now  in  very  exten 
sive  use,  seems  to  fulfil  any  requirement  of  a  good  abut 
ment,  see  fig.  122,  page  242.  B  B  is  the  bridge  seat,  and 
the  mass  T  T  takes  the  place  of  wings.  The  difference  of 
level  of  the  top  and  of  the  bridge  seat  depends  upon  the 
difference  between  the  height  of  the  bearing  of  the  lower 
chord  of  the  bridge,  and  grade.  The  line  of  contact  between 
the  earth  and  the  wall  is  shown  by  s  sr  s"  s"f.  The  length 
of  the  top  of  the  masonry  is  thus.  Suppose  the  slope  to  be 
one  and  one  half  to  one,  and  the  whole  height  thirty  feet, 
the  whole  horizontal  length  of  slope  is  then  forty-five  feet ; 
from  this  we  take  the  sum  of  the  horizontal  distances,  s  sr 
and  s'  /,  and  suppose  these  to  be,  respectively,  six  and  eight 
feet,  we  have  the  whole  operation  thus :  — 

30  x  11  — 6  +  8  =  45  — 14  =  31  feet. 

It  may  be  advisable  in  very  high  abutments  to  lighten  the 
masonry  by  an  arched  opening  as  in  fig.  123.  The  walls, 
also,  of  the  U  abutment  (see  fig.  124),  when  large,  may  be 
pierced  with  arches  to  save  masonry. 

Probably  the  cheapest  mode  of  bringing  a  bridge  to  the 
embankment  is  that  shown  in  fig.  125 ;  A  being  the  bridge 
seat  for  the  main  truss,  and  B  that  for  the  trussed  girder. 

c.  125. 


STONE   BRIDGES.  245 


PIERS. 

258.  The  thickness  of  a  pier  may  be  considered  either  as 
depending  upon  the  weight  of  the  superstructure,  or  as  re 
sisting  the  thrust  of  arches  or  braces.     For  the  first  require 
ment,  very  little  thickness  would  suffice ;  for  the  second,  it 
may  require  to  be  considerable.      The  objection   to  thick 
piers   is   the  expense,  and    the  contracting  too  much    the 
water-way ;  the  benefit,  a  large  bearing  surface,  and  in  stone 
bridges  where  there  are  several  continuous  spans,  a  saving 
of  centring ;  as  where  the  piers  are  not  able  to  resist  the 
thrust  of  the  arches,  they  must  all  be  carried  up  at  once. 

259.  Piers   supporting  truss   bridges,  require   very  little 
thickness  provided  a  good  foundation  is  obtained.      The 
following  table  shows  the  sufficient  dimensions  for  the  piers 
of  wooden  or  iron  trussed  bridges,  when  the  masonry  is  good. 
(See  First  Class  Masonry,  specification,  Chap.  IV.)     From 
ten  to  twenty  feet  in  height  the  latter  is  assumed  at  one 
twelfth ;  from  twenty  to  fifty  feet  in  height  at  one  twenty- 
fourth. 

Span.  Length  of  bridge  seat.         Width  of  seat. 

feet, 


20  to     40  feet, 

20  feet, 

4 

40  to     60    u 

20    " 

4J 

60  to     80    « 

22    " 

5 

80  to  100    « 

23    « 

51 

100  to  125    « 

23    " 

6 

125  to  150    « 

24    « 

61 

150  to  200    " 

24    " 

7 

260.  Upon  the  form  of  the  up-stream  end  of  the  pier,  or 
the  starling,  depends,  in  a  considerable  degree,  the  contrac 
tion  of  the  water-way.  In  sluggish  water  the  form  is  not 
of  much  importance,  but  in  swift  flowing  rivers  a  great  deal 
depends  upon  the  choice.  The  forms  in  use  are  the  rec 
tangle,  the  rectangle  terminated  by  right-lined  triangles,  and 

21* 


246  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

the  same  terminated  by  curved-lined  triangles,  and  finally 
the  ellipse. 

The  latter  is  that  which  causes  the  least  disturbance  to 
the  water,  but  is  also  the  most  costly. 

The  effect  of  gyration  at  the  shoulder,  deserves  notice,  as 
it  may  be  the  cause  of  the  ruin  of  the  foundation  when  the 
bottom  is  of  yielding  material. 

River  beds  being  porous,  springs  work  up  through  them 
with  a  force  equal  to  the  whole  depth  of  water ;  and  when 
ever  there  is  a  means  of  escape  for  such,  its  pressure  will 
act  upwards  against  any  structure  that  comes  within  its 
reach  ;  and  if  four  or  five  feet  deep,  is  capable  of  moving 
enormous  weights.  Such  springs  gave  a  great  deal  of 
trouble  at  the  foundation  of  the  United  States  Dry  Dock,  at 
Brooklyn,  N.  Y.  When  checked  in  one  place  they  burst 
up  in  another,  and  to  proceed  with  the  work  it  was  neces 
sary  to  allow  them  a  passage  through  which  to  flow. 

261.  However  proper  it  may  be  to  give  to  piers  the  proper 
form  to  cause  as  little  contraction  as  possible  to  the  water, 
it  is  no  less  necessary  to  give  them  strength  to  oppose  the 

Fig.  126. 


STONE  BRIDGES.  247 

shocks  to  which  they  are  subject  from  floating  ice,  timber 
and  shipping.  The  best  method  of  breaking  up  ice,  when 
it  comes  in  large  masses,  is  by  inclining  the  front  of  the 
pier,  as  shown  in  fig.  126.  The  angle  of  the  front  being 
inclined  from  30°  to  50°.  The  ice  running  up  this  slope 
breaks  by  its  own  weight,  and  falls  off  on  either  side. 

The  foundations  of  piers  may  be  protected  by  sheet 
piling,  (see  chap.  XII.,)  or  the  bottom,  if  soft,  may  be 
dredged  out  for  a  few  feet  and  filled  in  with  loose  rock. 

The  form  of  the  down-stream  end  is  not  of  so  much  im 
portance  as  of  the  upper  one,  but  deserves  consideration ; 
as  when  the  water  is  swift  or  the  bottom  soft  and  yielding, 
the  eddies  caused  by  sharp  angles  wear  upon  the  soil  in  a 
dangerous  manner. 


CHAPTER    XL 

MASONRY. 

STONES, 

262,  THE  varieties  of  this  material  most  commonly  used 
in   engineering   operations   are   granites,  limestones,  sand 
stones,  slates,  brick,  and  artificial  stones ;  the  latter  being 
made  by  compounding  clays,  limes,  and  cements. 

Rock  taken  from  the  surface,  which  has  been  exposed  to 
the  atmosphere,  is  of  an  inferior  quality  to  that  found  at  a 
depth  where  it  has  been  exposed  to  a  strong  pressure ;  and 
is  consequently  denser.  Therefore,  in  opening  a  quarry  it 
is  advisable  to  excavate  upon  a  hill-side  and  come  at  once 
to  the  sound  stone.  Rock  is  generally  found  in  beds, 
divided  by  joints  or  seams,  at  which  the  natural  adhesion 
is  broken  and  the  layers  are  easily  separated,  When  the 
quarry  shows  no  natural  line  of  separation,  one  may  be 
produced  by  drilling  a  line  of  holes  at  equal  distances  from 
each  other,  into  which  conical  steel  pins  are  driven,  and  the 
stone  splits ;  the  pins  being  placed  in  the  plane  of  the 
required  seam. 

263,  Stone  is  used  almost  entirely  to  resist  a  compressive 
strain ;  as  in  the  voussoirs  of  an  arch,  or  in  the  courses  of  a 
pier.      The    resistance   of    stone    to    crushing,   is   as   fol 
lows  :  — 


MASONRY.  249 

Pounds  per  square  inch. 

Granite   .         .         .         .         .         10,000  to  16,000 

Limestone 12,000  to  14,000 

Sandstone         ....  10,000 

Marble 9,000  to  14,000 

Firm,  hard  burned  brick  ....         2,600 

Yellow  burned  brick 1,500 

Redbrick 1,200 

Pale-redbrick 900 

Chalk 750 

264.  When  stone  cannot  be  found,  brick  forms  an  excel 
lent  substitute ;  being  made  from  clay  earths,  which  can  be 
found  in  almost  any  locality.     Bricks  are  well  fitted  for  nice 
work,  are  cheap,  and  easy  of  transport.     The   French,  at 
Algiers,  have  used  concrete,  rammed  in  boxes  so  as  to  make 
large  cubes  and  other  shapes.     The  structures  built  of  this 
material  are  found  to  be  very  nearly  if  not  quite  as  strong 
as  those  of  natural  rock. 

LIMES,  CEMENTS,  MORTARS,  AND   CONCRETES.      9 

265.  Nothing  is  more  important  in  the  construction  of 
masonry  than  good  cement ;  and  generally,  no  part  of  con 
struction  is  intrusted  to  more  ignorant  persons.     Under  the 
above    head   are   to   be   considered  limes,  cements,  sands, 
common  hydraulic  mortar,  and  concrete. 

266.  Lime  is  obtained  by  burning  off  the  carbonic  acid 
from  the  pure  limestones ;   when  it  is  put  up  in  air  tight 
barrels  and  is  unslacked  lime.     Natural  cements  are  com 
posed  of  pure  lime  mixed  with  argyle  magnesia,  iron,  and 
manganese.     Artificial   cements    are    prepared   by   mixing 
with  pure  lime,  calcined  clay,  forge  scales,  powdered  bricks 
which  are  underburnt,  and  other  materials  of  like  nature. 
Cements  made  thus  artificially,  are  as  good  as  those  natu 
rally  hydraulic. 


250  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Lime  is  termed  rich,  poor,  hydraulic,  and  eminently 
hydraulic,  according  to  its  properties. 

Rich  or  fat  limes  are  those  which  double  their  volume  in 
slacking  and  dissolve  in  fresh  water  to  the  last  particle. 
They  absorb  about  300  per  cent,  of  their  weight  of  water. 

Poor  limes  do  not  much  increase  their  volume,  do  not 
dissolve  completely,  and  absorb  200  per  cent,  of  water. 

Hydraulic  limes  set  in  fifteen  or  twenty  days  after  im 
mersion,  and  continue  to  harden  as  they  grow  older.  After 
one  year  their  consistency  is  about  that  of  hard  soap. 

Eminently  hydraulic  limes  set  in  five  or  six  days,  and 
continue  to  harden. 

Limes  are  said  to  set  when  they  will  bear,  without 
depression,  a  rod  of  ^  of  an  inch  diameter  loaded  with  ten 
or  twelve  ounces. 

NOTE. — The  following  test  was  applied  to  every  tenth  cask  of  Eosendale 
cement  used  upon  the  masonry  of  the  United  States  Dry  Dock  at  the  Brooklyn 
(N.  Y.)  Navy  Yard.  Cakes  two  inches  in  diameter  and  three  fourths  of  an  inch 
in  thickness,  after  being  immersed  five  days,  were  required  to  bear  a  rod  of  one 
twenty-fourth  of  an  inch  diameter  loaded  with  fifty  Ibs.  Two  bricks  united  with 
the  cement  and  immersed  five  days,  were  required  to  resist  one  hundred  Ibs.  be 
fore  separating.  The  following  shows  the  progress  of  hardening.  The  force 
required  to  thrust  a  rod  one  twenty-fourth  of  an  inch  in  diameter  through  a  cake 
three  fourths  of  an  inch  in  thickness,  was,  after 

24  hours,  .        .        .        65  Ibs. 

48     "  .         .         .         .     70    " 

72     "      .  .         .         .         75    " 

15  days,  .        .        .        .  150   " 

50     "    .  .         .         .         390    " 

SAND. 

267.  Sand  is  the  product  of  the  decomposition  of  granitic 
and  schistose  rocks,  and  weighs,  per  unit  of  bulk,  somewhai 
less  than  one  half  of  the  rock  producing  it ;  owing  to  the 
spaces  between  the  grains.  The  amount  of  lime  necessary 


MASONRY.  251 

to  fill  these  spaces  must  be  known  before  we  can  form  a 
solid  mass  with  the  least  lime.  The  amount  of  void  may 
be  found  by  filling  a  measure  with  sand,  and  then  pouring 
in  water :  the  volume  of  water  is  that  of  the  spaces.  In 
pebbles  of  one  half  inch  in  diameter  the  void  amounts  to 
about  one  half,  in  gravel  about  five  twelfths,  in  common 
sand  two  fifths,  and  in  very  fine  sand,  one  third.  Clean 
sharp  sand  obtained  from  the  beds  of  rivers  is  the  best  for 
mortars. 

268.  In  mixing  the  ingredients  for  mortar,  the  lime   is 
first  spread  on  a  platform  and  wet  by  sprinkling  with  water, 
which  causes  it  to  give  off  a  great  deal  of  heat  and  vapor, 
and  fall  into  a  powder.     The  sand  is  then  applied,  and  the 
whole  brought  with  water  to  a  consistent  paste. 

The  proportions  for  common  mortar  for  dry  work  are 

Sand,  .  .  1\  to  2 
Lime,  ...  \ 

It  is  well  always  to  use  a  small  quantity  of  cement ;  the 
parts  which  have  in  practice  been  found  perfectly  satisfac 
tory  are 

Cement,  ...  1 
Lime,  ....  3 
Sand,  ...  6 

For  hydraulic  mortar  the  following  proportions  have  been 
used  with  success :  — 

Cement,  ...  2 
Sand,  ....  3 

269.  Concrete  is  made  by  mixing  broken  stone,  brick,  or 
shells,  with  cement  mortar ;  it  is  used  for  foundations,  back 
ing  of  arches,  and  for  making  artificial  stone.     The  com 
mon  proportions  are 


252  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Cement,  .  .  1  or  2 
Sand,.  ..  .  11  or  3 
Broken  stone,  .  5  or  10 

The  cement  and  sand  are  first  mixed  as  for  cement 
mortar;  the  broken  stone  is  added  and  the  whole  well 
mixed  and  immediately  applied  before  it  has  time  to  set. 
Both  concrete  and  cement  mortar  should  be  made  as 
required  for  use,  and  in  no  case  applied  after  standing  over 
three  hours. 

FLASHING   MORTAR. 

270.  Flashing  consists  of  a  thin  coat  of  cement  mortar 
made  with  a  very  large  part  of  cement.     It  is  used  to  pro 
tect  the  face  of  walls  exposed  to  the  wet ;  such  as  the  top 
of  arches.     Stone  liable  to  disintegration  may  be  protected 
by  flashing. 

POINTING   MORTAR. 

271.  Pointing  is  used  to  protect  the  joints  of  masonry, 
and  is  made  by  mixing  cement  and  sand  with  a  minimum 
of  water.     The  joint  is  first  cut  out  to  the  depth  of  from 
one  half  to   one  inch,  carefully  brushed  clean,  moistened 
with  water,  and  filled  with  the  mortar,  which  is  well  rubbed 
with  a  steel  tool.     To  give  architectural  effect,  plaster  of 
Paris  (Gypsum)  is  sometimes  used  in  pointing. 

GROUT. 

272.  Grout  is  thin-tempered  mortar,  composed   almost 
entirely  of  cement  and  water.     It  is  run  into  the  joints,  and 
is  useful  in  filling  crevices   in   masonry  which  cannot  be 
filled  with  mortar. 


MASONRY.  253 

CONSTRUCTION  OF  ARCHES. 

273.  The  foundations  being  secured,  and  the  piers  and 
abutments  being  carried  up  to  the  springing  line  of  the 
arch,  the  centres  are  carefully  adjusted  to  their  places  and 
the  arch  is  commenced.  When  the  voussoirs  begin  to  bear 
upon  the  centre  (which  is  when  the  angle  of  the  joint  with 
the  horizontal  is  greater  than  the  angle  of  repose  of  one 
stone  upon  another),  the  frame  is  liable  to  change  of  form, 
(particularly  when  the  arch  is  flat,)  which  must  be  provided 
for  by  counter  loading  the  centre  in  various  points  as  the 
work  proceeds.  Great  care  should  be  taken  to  make  each 
stone  point  in  the  direction  of  the  radius  of  the  arch.  To 
do  this  effectually,  their  thickness  should  be  marked  upon 
the  outer  rib  of  the  centre.  The  line  of  the  joint  may  then 
be  fixed  by  a  straight-edge  placed  both  on  the  centre  and 
the  rib  mark,  or  by  a  template  so  cut  that  when  one  side  is 
level  the  other  shall  stand  at  the  proper  angle.  Excess  of 
weight  upon  one  side  of  the  centre  causes  a  depression  at 
that  point,  and  a  corresponding  rise  at  the  opposite  side  of 
the  arch.  Both  sides  being  loaded,  the  haunches  settle,  and 
the  crown  rises.  The  point  where  the  centre  is  first  loaded 
will  determine  the  point  where  the  frame  is  to  be  tempo 
rarily  weighted.  Such  precautions,  however,  need  only  to 
be  taken  in  arches  of  over  fifty  feet  span,  unless  the  curve 
is  quite  flat.  The  keystone  should  be  put  into  the  proper 
place,  but  not  driven  until  the  rest  is  finished.  The  back 
joints  are  then  closely  wedged  and  cemented  with  thin  tem 
pered  mortar,  and  the  whole  is  left  to  set.  The  masonry  of 
the  spandrels  is  brought  up  to  about  one  fourth  the  height 
of  the  arch,  or  enough  to  prevent  by  their  weight  any 
change  of  form  of  the  curve.  The  centres  are  then  struck 
and  the  soffit  and  voussior  joints  cleaned  and  pointed.  The 
facing  and  road-way  may  next  be  carried  up ;  the  parapet 

22 


254 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  127. 


128. 


coping  and  drains  fin 
ished  off  ;  and  the 
whole  pointed.  Para 
pets  are  shown  in  figs. 
127  and  128.  The 
spandrels,  fig  129,  may 
be  carried  up  solid  or 
hollow  ;  their  weight 
must  be  enough  to 
stiffen  sufficiently  the 
arch.  It  should,  at 
least,  be  carried  up 
solid  to  the  line  c  cc\ 


Fig.    129. 


the  shaded  mass  being  of  well-cemented  rubble.  Above 
this  the  filling  may  be  of  masonry,  solid  or  arched,  or  even 
of  well-rammed  layers  of  earth.  The  road- way  should,  in 
all  cases,  be  well  drained,  that  the  water  may  not  sink 
through  to  the  masonry. 

The  apparatus  for  handling  stone  (cranes,  lewises,  and 
derricks)  is  much  better  understood  by  inspection  than  by 
description. 

Wherever  walls  support  masses  of  earth,  the  thrust  may 
be  somewhat  lessened  by  ramming  the  earth  behind  the 
wall  in  layers  inclining  backward.  In  laying  up  the  corners 


MASONRY.  255 

each  should  be  well  cleaned  and  moistened  before  the 
mortar  is  laid  upon  it.  When  a  stone  has  been  once  placed 
upon  the  mortar  bed,  it  should  not  be  moved  at  all  laterally, 
but  may  be  gently  mauled  on  top. 

CULVERTS  AND  DRAINS. 

274.  Small  culverts  are  made  by  covering  two  side  walls 
with  large  flat  stones;  the  bottom  being  paved  with  stone 
at  least  nine  inches  deep,  laid  dry.  The  general  dimensions 
of  such  structures  depend  somewhat  upon  the  class  of  ma 
sonry,  but  as  this  is  generally  the  third  or  fourth,  will  not 
vary  much. 

Opening.  Side  walls.  Cover.  Heads. 


2X2 

3    X2 

12 

2X10 

2X3 

3    X3 

12 

3X10 

3X3 

3    X3 

12 

3XH 

3X4 

3^X4 

15 

4X12 

4X4 
4X5 
5X5 

3^X4 
3^X5 
4    X5 

15 

18 
18 

4X13 
5X15 
5X  16 

5X6 

4    X6 

18 

6X18 

Figs.  130,  131,  and  132,  show  plans  for  culverts  of  from 
5  to  25  feet  span. 

¥ig.  130. 


256 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  181. 


Fig.  132. 


RETAINING  WALLS. 

275.  A  wall  made  to  sustain  a  mass  of  earth  or  water, 
to  resist  overthrow,  requires  a  certain  thickness.  A  body  of 
earth  assumes  what  is  termed  the  natural  slope,  the  incli 
nation  of  which  depends  upon  the  adhesion  of  the  soil,  but 
may  be  taken  as  one  and  one  half  horizontal,  to  one  vertical, 
(1£  to  1),  as  an  average. 

The  problem  is,  knowing  the  height  of  the  wall  and  the 
form  of  the  mass  of  earth  to  be  supported,  to  find  the  thick 
ness  of  the  wall. 

Let  A  B  6  F,  represent  the  thickness  of  the  wall.  Its  cen 
tre  of  gravity  is  at  O,  and  is  horizontally  projected  at  m. 
The  centre  of  gravity  of  the  thrusting  triangle  of  earth,  B  4  6. 
is  C,  (formed  by  the  cutting  of  lines  joining  any  two  angles 
to  the  centre  of  the  opposite  sides,)  is  horizontally  pro 
jected  at  Ca,  and  the  horizontal  component  of  the  thrust  is 
exerted  at  2,  tending  to  overthrow  the  wall  with  a  lever 
age,  6  2. 


257 


The  overthrowing  power  is,  then,  the  area  of  the  triangle 
B  4  6  X  the  weight  of  the  unit  of  area  X  the  leverage  6  2. 
And  the  resisting  power,  the  area  A  B  X  B  6  X.the  weight 
of  a  unit  of  area  by  one  half  breadth,  or  m  6 ;  or,  callings 

22* 


258  HANDBOOK  OF  RAILROAD  CONSTRUCTION. 

the  weight  of  the  wall,  and  w'  that  of  the  triangle,  B  4  6, 
and  L  and  L'  the  leverage  respectively  of  the  wall  to  resist 
and  of  the  earth  to  overthrow  ;  we  must  have  at  least 

wL-=.w'  If,  .,-  * 

and  to  insure  stability, 

wL>wr  Lr 
or, 

r 

: 


and  as  L  =  half  base  finally,  the  thickness,  or 


276.  Example.  —  Let  the  height  of  wall  be  twenty  feet, 
slope  one  and  one  half  to  one  ;  if  a  cubic  foot  of  earth 
weighs  one  hundred  Ibs.,  and  of  masonry,  one  hundred  and 
sixty  Ibs.,  we  have  the  overthrowing  force, 

2J>  x  15  X  1  X  100  X  ^°, 

and  the  resisting  force,  (assuming  the  thickness  as  eight 
feet,  in  order  to  get  the  area), 

20  X  8  X  1  X  160  X  I- 
Or  performing  the  operations, 

For  overthrowing,       *.;•-*  .     "  V       100,000  Ibs. 
For  resisting,     .     *  .-  *  '.    ;*"  '-.        v    102,400  Ibs. 

If  the  wall  in  place  of  retaining  only  the  mass  B  4  6,  re 
tains  the  bank  B  E  Fa,  the  pressure  will  evidently  be  in 
creased.  The  centre  of  gravity  of  the  trapezoid  B  E  Fa  6, 
is  at  C',  which  is  horizontally  projected  at  C/a,  and  the  hor 
izontal  component  of  the  thrust  acts  at  3  with  the  leverage 
63. 


MASONRY. 


259 


Fig.  134. 


Any  superincumbent  load,  as  a  train  of  cars  at  E  Fa,  will 
again  increase  the  pressure,  not  only  by  reason  of  weight, 
but  from  shocks  and  vibration. 

For  resisting  lateral  pressure,  the  beds  of  masonry  are  best 
when  rough  dressed.  For  vertical  loads,  hammer  dressed 
beds  are  the  best. 

The  leverage  of  resistance  is  very  much  increased  by  bat 
tering  the  wall  in  front,  as  at  AD.  The  centre  of  gravity 
is  then  horizontally  projected  at  w',  but  the  distance  D  m' 
is  much  greater  than  F  m. 

The  amount  of  masonry  remaining 
the  same,  by  decreasing  the  top,  and 
increasing  the  base,  the  strength  is 
very  much  increased. 

When  retaining  walls  are  exposed 
to  shocks  or  pressures  in  special 
directions,  they  may  be  very  much 
aided  by  buttresses  opposing  directly 
such  forces,  as  in  fig.  134. 

The  increase  of  strength  thus  made 
by  a  small  bulk  of  masonry  is  very 
great. 

All  abutments,  wing-walls,  and  side 
walls  of  culverts,  come  under  the 
head  of  retaining  walls. 

When  the  face  of  the  wall  does  not 
by  its  position  admit  of  buttresses,  as 
in  fig.  134,  it  may  be  dovetailed  into 
the  earth;  the  latter  being  firmly 
rammed  around  the  masonry,  as  in 
fig.  135. 


260  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Pig.  135. 


277.    The  weig-ht  of  the  different  earths  and  stones  are 
shown  in  the  following  table. 

Name  of  material.  Weight  per  cubic  foot. 

Brick,  common          .         .         .         .  97  to  125 

Brick,  stock 115  to  135 

Brickwork,  (average,)        .         .         .  90  to    95 

Chalk,          .         .         .         .         .         .  144  to  166 

Granite, 164  to  187 

Marble, Ill  to  117 

Mortar,  (hair,)  dry  .         .         .         .  80  to    86 

Puzzolano, 160  to  178 

Slate, 157  to  180 

Stone,  (average,)  .         .         .         .  140  to  150 

Clay,  (common,)        .         .         .         .  110  to  125 

Clay  and  gravel,  .         .         .         .  150  to  170 

Earth,  common,         .         .         .         .  95  to  126 

Gravel,        .    ; 100  to  110 

Quick-lime,      .        .         .         .         .  50  to    55 

Quartz  sand, 170  to  175 

Common  sand,  .         .         .         .  88  to    93 

Shingle,       .    -;*         .         .         .         .       88  to    92 
Earth,  loose      .        ,;  ....--^  .r  ,,:.  •      .  90  to    95 

Stone  work,  (hewn,)  in  wall,         .         .  160  to  175 

Stone  work,  (unhewn,)  in  wall,          .  125  to  140 


CHAPTEK    XII 
FOUNDATIONS. 


278.   FOUNDATIONS  may  be  divided  into  four  classes. 

Those  onjirm  dry  land. 

Those  on  unfirm  dry  land. 

Those  on  solid  bottom,  under  water. 

Those  on  unfirm  bottom,  under  water. 

Foundations  upon  firm  dry  land  require  only  to  be  placed 
at  a  sufficient  depth  to  be  out  of  the  way  of  frost ;  varying 
from  one  foot  in  the  Southern,  to  two  and  three  feet  in  the 
Middle,  and  four  and  five  feet  in  the  Northern  States.  The 
first  course  should  consist  of  small,  flat  stones  placed  dry, 
but  well  packed  by  hand,  upon  the  bottom ;  upon  the  top 
of  this  layer,  the  mortared  or  cement  masonry  should  be 
commenced.  The  object  of  the  first  course  of  small  stones 
is  to  apply  the  weight  of  the  superincumbent  masonry  as 
equally  as  possible  to  the  ground.  All  boulders  and  rounded 
stones  should  be  carefully  kept  out  of  the  foundation. 

Unfirm  soils  are  prepared  by  driving  piles,  upon  which 
a  platform  holding  the  masonry  is  placed ;  or  by  placing 
the  lower  courses  directly  upon  the  heads  of  the  piles. 


262  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

Sand  piles  are  made  either  by  driving  and  withdrawing  a 
wooden  pile  and  filling  the  hole  thus  made  with  sand ;  or 
by  digging  trenches  and  filling  such  with  sand.  The  ap 
plied  weight  is  thus  spread  over  the  entire  surface  of  the 
sides  and  bottom,  instead  of  being  placed  upon  the  bottom 
only.  When  the  weight  of  a  heavy  structure  is  thrown 
upon  a  few  small  points  of  support,  they  may  be  made  the 
piers  and  abutments  of  a  series  of  inverted  arches,  by  which 
the  whole  surface  beneath  the  structure  is  made  to  assist  in 
bearing  the  load.  Foundations  upon  yielding  or  sandy  and 
wet  soils  may  be  secured  by  piling  around  the  whole  struc 
ture;  by  which  the  earth  is  kept  from  spreading.  Foun 
dations  upon  dry  land  do  not  generally  give  much  trouble 
to  the  engineer;  but  operations  carried  on  under  water 
require  all  the  science  and  patience  that  he  is  master  of. 
279.  Three  methods  of  founding  under  water  may  be 

noticed, 

By  driving  piles. 

By  coffer-dam. 
By  caisson. 

In  very  shallow  water,  where  no  danger  arises  from  con 
tracting  the  water-way,  we  may  throw  in  loose  stones  until 
the  surface  is  reached;  and  commence  thereon  the  lower 
courses  of  the  masonry.  This  is  termed  "  Enrockment." 

PILE  DRIVING. 

This  operation  has  for  its  object  the  consolidation  of  nat 
urally  weak  bottoms ;  for  piles  driven  close  together  tend  to 
prevent  that  compression  that  might  take  place  under  a 
heavy  structure.  Piles  may  resist  either  by  friction  against 
the  soils  through  which  they  are  driven,  or  by  bearing  upon  a 
firm  superstratum  at  too  great  a  depth  to  be  reached  by 
uncovering.  Piles  driven  in  clay  have  sometimes  acted  as 


&fi  FOUNDATIONS.  263 

a  conductor  to  water,  which,  insinuating  itself  along  the 
side  of  the  wood,  produced  settling  which  would  not  other 
wise  have  taken  place. 

Experience  has  shown  that  four  feet  apart  from  centre  to 
centre,  when  there  is  a  good  substratum,  is  near  enough  to 
bear  the  heaviest  loads. 

The  fact  that  a  pile  refuses  to  enter  further,  does  not  show 
that  it  has  reached  a  bed  strong  enough  to  bear  the  required 
load  ;  for  though  it  may  bear  upon  a  solid  bottom,  or  resist 
penetration  by  side  friction,  when  the  load  has  been  for 
some  time  upon  the  pile,  it  may  be  found  too  weak  to  stand. 
Piles  have  in  some  cases  refused  to  enter  the  ground  from 
the  blow  of  a  1,500  Ibs.  ram,  falling  twenty  feet,  when  first 
driven,  arid  have  afterwards  gone  down  three  feet  from  a 
ram  of  1,000  Ibs. 

The  following  formula,  showing  the  resistance  which  a 
pile  should  offer,  is  given  by  Weisbach  in  Mechanics  of  En 
gineering,  Vol.  I.  p.  285.  First,  when  the  ram  remains 
upon  the  pile  after  the  blow, 

P     _'2 

" 


And,  second,  when  the  ram  does  not  remain  upon  the  pile, 

(Gr     V 
G+G')  ><  GH~ 

Example.  —  A  pile  weighing  five  hundred  Ibs.  is  driven 
two  feet,  by  forty  blows  of  a  1,000  Ibs.  ram  falling  six  feet. 
Required  the  weight  which  may  be  safely  supported  by  the 
pile  without  further  penetration. 

The  notation  in  the  formula  above  is  thus, 

G=  the  weight  of  the  pile. 
G'  =  the  weight  of  the  ram. 
H=  the  fall  of  the  ram. 


264  HANDBOOK   OF  RAILROAD  CONSTRUCTION. 

s  =  penetration  per  blow. 
P=  the  weight  in  Ibs. 

The  penetration  per  blow  will  be  ^  or  .05  feet  ;  and  the 
formula  for  the  second  case 


Of  which  one  tenth  or  one  twelfth  only  is  the  maximum 
load  which  should  be  placed  upon  the  pile  permanently. 
The  surest  test  of  the  power  of  a  pile  is  to  load  it  tempo 
rarily,  when  the  time  and  place  admit. 

Perronet  considered  fifty  tons,  or  112,000  Ibs.  as  not  too 
great  for  a  twelve  inch  pile  ;  and  allowed  twenty  -five  tons 
for  a  pile  of  nine  inches  in  diameter. 

That  the  point  of  the  pile  may  not  be  shattered  by  con 
tact  with  the  hard  earth,  an  iron  shoe  is  sometimes-  fitted 
to  the  lower  end  ;  and  that  the  head  may  not  split,  an  iron 
ring  is  driven  on  to  the  top. 

The  force  of  the  blow  given  by  a  ram  depends  upon  the 
weight  of  the  ram  or  monkey,  and  upon  the  velocity  at 
which  it  strikes  the  pile  ;  the  velocity  depends  upon  the 
height  from  which  it  falls.  The  velocities  of  bodies  falling 
freely  being  as  the  times,  and  the  spaces  fallen  through  as 
the  squares  of  the  times,  we  have  the  following  rules  ;  and 
from  them  the  table  succeeding. 

Given  the  velocity  of  a  body  to  find  the  space  through 
which  it  must  fall, 

(Velocity  in  feet  per  secondX2 
—  g  —  —I  =  space  in  feet. 

Thus  a  weight  to  acquire  a  velocity  of  two  hundred  feet 
per  second,  must  fall  through  a  height  of 


FOUNDATIONS.  265 

Given  the  space  fallen  through,  to  find  the  velocity. 


y/ height  in  feet  X  64.3  =  velocity  in  feet  per  second. 
Thus  the  velocity  of  a  body  falling  twenty  feet  will  be 


y/20  X  64.3  =  36  feet  per  second. 

Momentum  is  the  product  of  weight  by  velocity;  there 
fore,  to  find  the  force  of  the  blow  given  by  a  ram  of  given 
weight,  falling  a  given  height,  we  find,  first,  the  velocity  by 
rule  two.  Also,  given  the  weight  of  ram,  the  necessary 
velocity  to  produce  any  required  effect  being  found,  it  is 
easy  to  find  the  height,  and  the  reverse. 

Examples. —  Suppose  we  have  a  ram  weighing  2,000  Ibs. 
and  wish  to  strike  a  blow  of  25,000  Ibs. ;  the  velocity  must 
be 

25000 

2QQQ  =  12f  feet  per  second ; 

and  to  acquire  that  velocity,  the  height  fallen  must  be  (rule 

one) 

/ 1 21\ 2 

=  2.43  feet. 


Again,  if  we  have  a  pile-engine  which  admits  of  a  fall 
of  fifteen  feet,  and  we  wish  to  strike  a  blow  of  18,000  Ibs., 
we  first  find  the  velocity  (rule  two)  thus :  — 


y/lo  X  64.3  =  31  feet  per  second  nearly, 
whence  the  weight 

18000 


31 


=  581  Ibs. 


The  form  of  the  common  pile-engine  is  too  well  known 
to  need  description. 

23 


266  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Mr.  Nasmyth's  system  of  pile-driving  consists  in  forcing 
the  pile  into  the  ground  by  a  great  number  of  blows  follow 
ing  each  other  in  rapid  succession.  Piles  were  driven  by 
his  engine  at  the  United  States  Dry  Dock,  at  Brooklyn,  (N. 
Y.,)  as  follows :  A  pile  was  sunk  fifty-seven  feet  by  a  ham 
mer  of  4,500  Ibs. ;  it  was  driven  forty-two  feet  in  seven 
minutes  by  three  hundred  and  seventy-three  blows. 


MITCHELL'S   SCREW  PILE. 

Mitchell's  screw  pile  is  a  cast-iron  column,  around  the 
lower  part  of  which  is  a  spiral  flange.  It  is  screwed  into 
the  ground,  and  offers  great  resistance  to  vertical  pressure, 
on  account  of  the  large  bearing  surface  obtained. 


DR.  POTTS'S  ATMOSPHERIC  SYSTEM. 

280.  All  methods  of  placing  foundations  in  difficult  posi 
tions  must  yield  to  the  above  plan,  which  consists  in  ex 
hausting  the  air  from  a  hollow  cast-iron  cylinder ;  when  the 
pressure  upon  the  surface  of  the  ground,  outside  of  the 
cylinder,  forces  the  earth  immediately  under  the  pile  to  its 
interior ;  at  the  same  time  the  pile  sinks  into  the  opening 
thus  made,  both  by  its  weight  and  by  the  atmospheric 
pressure  from  the  outside.  The  earth  is  moved  from  the 
interior  of  the  pile ;  and  when  sunk  to  the  necessary  depth, 
the  interior  is  filled  with  concrete. 

A  very  successful  application  of  the  above  system  was 
made  at  the  Godwin  Sands,  at  the  mouth  of  the  Thames 
River,  (England).  There,  sands  change  their  position  with 
every  violent  storm,  and  are  yet  so  compact  that  a  steel  bar 
could  be  driven  only  eight  feet  with  a  sledge  hammer ;  and 
a  pointed  rod  three  inches  in  diameter,  when  sunk  thirteen 


FOUNDATIONS.  267 

feet  deep,  required  forty-six  blows  from  a  one  hundred  Ibs. 
ram  falling  ten  feet  to  drive  it  one  inch.  But  a  hollow  pile 
two  and  a  half  feet  in  diameter  was  sunk  seventy-eight  feet, 
at  the  rate  of  ten  feet  per  hour  for  a  part  of  the  time.  In 
case  of  meeting  with  rock,  the  pile  may  be  converted  into  a 
diving-bell,  and  the  obstruction  moved. 

The  pile  is  cast  in  lengths  of  ten  or  twelve  feet,  and 
flanged  together  with  cemented  joints. 

In  founding  a  bridge  at  Rochester,  (England,)  a  pile  of 
this  nature  was  loaded  with  thirty  tons  of  iron  rails,  which 
caused  a  settlement  of  three  fourths  of  an  inch.  The  rails 
being  removed  and  the  air  exhausted,  by  a  single  effort  the 
pile  descended  six  and  a  half  feet.  One  hundred  tons  of 
rails  were  then  placed  upon  the  pile,  when  the  settlement 
was  again  three  fourths  of  an  inch.  (This  small  depression 
was  owing  to  the  compression  of  the  soil.) 

The  piles  supporting  the  Shannon  bridge,  on  the  Midland 
Great  Western  Railroad,  (England,)  were  sunk  by  this 
system ;  and  are  ten  feet  in  diameter,  and  filled  with  con 
crete. 

After  wooden  piles  have  been  driven,  they  are  cut  off  at 
the  bottom  to  receive  the  lower  courses  of  the  masonry. 
In  some  cases  square  timber  caps  are  placed  upon  the  pile 
heads,  and  thereon  a  plank  floor.  In  others,  the  spaces  be 
tween  the  piles  are  filled  with  cement  and  concrete. 


COFFER-DAM. 

281.  In  founding  in  water  from  five  to  twenty-five  feet 
deep,  a  contrivance  called  a  "  coffer-dam,"  is  sometimes  used. 
It  is  formed  by  driving  a  double  or  triple  row  of  piles 
around  the  foundation ;  which  rows  are  made  water  tight, 
either  by  tongued  and  grooved  square  piles,  or  by  round 


268  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

piles,  to  which  is  fastened  a  sheathing  of  plank.  The  space 
between  the  courses  of  piling  is  emptied  of  water  and 
packed  closely  with  clay* or  other  material  impervious  to 
water.  The  interior  of  the  dam  is  then  pumped  dry  and 
the  masonry  laid  as  on  dry  land.  The  thickness  of  the  dam 
depends  upon  the  depth  of  water;  the  pressure  upon  the 
lower  part  being  of  course  much  greater  than  that  at  the 
upper.  If  it  was  considered  as  a  mass  resisting  by  its 
weight,  overthrow  from  the  pressure  of  the  water,  the  thick 
ness  would  be  easily  calculated.  Thus,  if  the  water  is 
twenty  feet  deep  the  whole  hydrostatic  pressure  upon  each 
lineal  foot  of  the  dam  is  20  X  1  X  10  X  62i  —  12,500  Ibs. ; 
and  as  the  weight  of  water  increases  in  the  order  of  the 
terms  of  an  arithmetical  progression,  as  also  the  pressure, 
it  may  be  expressed  by  the  elements  of  a  triangle,  of  which 
the  height  is  the  depth ;  and  as  the  centre  of  gravity  of  a 
triangle  is  at  two  thirds  of  the  height  from  the  vertex,  the 
pressure  may  be  regarded  as  concentrated  at  one  third  of 
the  depth  from  the  bottom ;  and  the  leverage  of  the  above 
12,500  Ibs.  is 

20 

-  =  6.67  feet; 

o 

and  the  overthrowing  force  is  83,375  Ibs.  The  resisting 
force  of  a  clay  dam  twenty  feet  high  and  ten  feet  thick, 
would  be 

20  X  10  X  HO  X  Y  ~  110>000  !bs. 

Determining  the  thickness  thus,  would  make  the  dam, 
when  in  deep  water,  very  thick ;  and  it  is  generally  best  to 
brace  the  inside  against  the  ground,  and  when  the  masonry 
will  admit,  against  that. 

Dams  of  the  following  thickness  have  proved  perfectly 
secure :  — 


FOUNDATIONS.  269 

Depth  of  water.  Thickness. 

6  feet.  3  feet. 

10     «  5     « 

15     «  8     " 

20     "  12     " 

25     "  14     " 

The  best  form  for  a  large  coffer-dam  is  circular,  or  ellip 
tical  ;  as  the  pressure  is  thus  resisted  more  equally  in  all 
places  than  when  there  are  flat  sides  and  angles  in  the  plan. 

To  keep  the  dam  dry  while  the  work  is  going  on,  pumps 
are  rigged  along  one  side  of  the  dam  the  lower  ends  of 
which  are  placed  in  a  trench  or  well  which  drains  the  bot 
tom. 

The  piers  of  the  Victoria  bridge  at  Montreal,  (Canada,) 
are  put  down  by  coffer-dams.  Some  of  the  piers  being  in 
but  few  feet  of  water,  and  upon  a  rocky  bottom,  which  did 
not  admit  of  the  driving  of  piles ;  the  dams  for  such  were 
built  in  sections,  floated  to  the  site  and  anchored. 


FOUNDATION  BY  CAISSON. 

282.  In  deep  water  the  coffer-dam  becomes  very  expen 
sive,  on  account  of  the  size  and  length  of  the  piling,  and 
the  quantity  of  bracing  required.  In  such  cases  recourse  is 
had  to  the  caisson ;  which  is  simply  a  box  in  which  the  ma 
sonry  is  built,  and  afterwards  sunk  to  the  proposed  site. 
The  manner  of  putting  down  a  piece  of  masonry  by  cais 
son  will  best  be  shown  by  an  example. 

Suppose  we  wish  to  sink  a  pier  thirty  feet  long,  twenty 
feet  high,  and  six  feet  wide,  in  twenty  feet  of  water. 

Let  the  caisson  bottom  be  of  two  courses  of  square 
12  X  12  timbers,  fastened  strongly  at  right  angles  to  each 
other.  Let  the  courses  of  masonry  be  two  feet  thick.  As- 

23* 


270  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

sume  the  weight  of  a  cubic  foot  of  stone  as  one  hundred 
and  sixty  Ibs.,  a  cubic  foot  of  wood  at  thirty,  and  of  water 
sixty  -two  Ibs.  per  foot. 

Every  floating   body  will  sink  until  it  has  displaced   a 
quantity  of  water  equal  to  its  own  weight. 

If  the  bottom  is  ten  feet  wide  and  thirty-five  feet  long,  it 
will  weigh 

35  X  10  X  2  X  30m  21,000  Ibs. 

one  course  of  masonry  weighs 

30  X  6  X  2  X  160  =  57,600  Ibs. 

one  course  of  side  timbers,  12  X  12,  which  are  laid  upon  the 
sides  of  the  raft, 

(2  x  35  +  2  X  8)  X  30  =  2,580  Ibs. 

Now  load  the  bottom  with  one  course  of  masonry  and 
three  courses  of  side  timbers,  and  we  have 

Stone        ....  57,600  Ibs. 

Bottom  of  caisson  .         .  21,000" 

Three  side  courses     .         .     -      7,740  " 

In  all    .....  86,340  « 

which  divided  by  62,  gives  1,392;  which  divided  by  the 
area  of  the  caisson  bottom,  gives 

1392 


or  nearly  four  feet,  for  the  depth  at  which  the  caisson  will 
float.  This  leaves  the  sides  one  foot  above  the  water  sur 
face. 

Putting  on  a  second  course  of  masonry  and  three  more 
side  courses  of  timber,  we  have 


FOUNDATIONS.  271 


Floor   .... 

.     21,000  Ibs. 

Two  courses  masonry 
Six  side  courses    . 

115,200  « 
.     15,480  " 

In  all 

.       151,680  " 

which  divided  by  62,  and  by  350,  gives  seven  feet  very 
nearly;  leaving  the  top  one  foot  above  the  surface. 

In  the  same  manner  we  proceed  until  the  caisson  grounds 
upon  the  bed,  which  has  been  previously  prepared,  either  by 
pile-driving  or  by  dredging.  The  bottom  being  reached, 
the  sides  are  taken  off,  and  the  masonry  remains  upon  the 
floor.  The  caisson  may  at  any  time  be  grounded  by  filling 
with  water,  and  may  be  raised  again  by  pumping  out. 
The  masonry  may  be  laid  either  from  barges  or  rafts  at  the 
site,  or  at  the  shore.  Guide  piles  are  necessary  to  insure 
the  descent  in  the  proper  manner,  and  to  prevent  overturns. 

In  laying  stone  under  water,  it  is  to  be  remembered  that 
masonry  submerged  loses  T%2F  nearly  of  its  weight,  and  is 
consequently  more  liable  to  be  injured  by  shocks  than  when 
above  the  surface. 


CHAPTEE    XIII 

SUPERSTRUCTURE. 


253.  NOTHING  aids  more  the  proper  accomplishment  of 
any  object  than  a  correct  idea  of  what  is  wanted.  The  fol 
lowing  definition  is  given  by  Mr.  W.  B.  Adams,  of  what 
good  superstructure  should  be  :  — 

"  The  principal  requirements  of  permanent  way  are : 
That  it  shall  be  well  drained,  especially  in  contiguity  to  the 
substructure  ;  that  the  weight  and  damaging  power  of  the 
locomotives  and  rolling  stock  should  be  considered  the  data 
for  calculation  ;  that  the  strength,  hardness,  and  tenacity 
of  rails,  and  the  immobility  of  the  substructure  should  be 
adapted  to  the  hardest  work  to  which  the  railway  is  to  be 
subjected ;  that  the  substructure  should  have  an  amount  of 
bearing  surface  proportioned  to  the  load  to  be  borne,  and 
the  nature  of  the  rail  and  ballast;  and  a  sufficiently  fair 
hold  in  the  ground  to  prevent  looseness  or  lateral  motion, 
from  the  side  lurches  of  the  engines  and  trains  ;  that  the 
rails  should  possess  so  much  vertical  and  lateral  stiffness, 
either  in  themselves  or  in  their  fastenings,  as  to  prevent  all 
deflection;  and  have  sufficient  hardness  of  surface  not  to 
laminate  or  to  disintegrate  beneath  the  rolling  loads ;  also, 


SUPERSTRUCTURE.  273 

to  have  sufficient  breadth  or  tread  surface  to  diminish  the 
crushing  effect  of  the  wheels. 

"  They  should  be  as  smooth  as  possible,  to  prevent  con 
cussion,  and  be  laid  at  the  proper  angle,  and  the  curves 
regularly  bent,  so  as  to  insure  the  accurate  tread  of  the 
wheels.  The  joints  should  be  so  made  that  the  rails  may 
practically  become  continuous  bars,  yet  with  freedom  to 
contract  and  expand  without  being  too  loose.  And  with 
all  this  there  should  be  interposed  between  the  rails  and  the 
solid  ground,  some  medium  sufficiently  elastic  to  absorb  the 
effect  of  the  blows  of  the  wheels,  without  being  crushed  or 
forced  down  into  the  ballast,  and  yet  stiff  enough  to  keep 
the  upper  surface  of  the  rails  in  a  uniform  plane." 


TIMBER-WORK. 

284.  The  timber-work  supporting  the  rails  consists  either 
of  cross  ties  of  wood,  hewn  flat  on  top  and  bottom,  of  di 
mensions  from  6  X  7  to  7  X  9,  and  2J  or  3  feet  longer  than 
guage ;  or  of  longitudinal  sawed  timbers  rectangular  in  sec 
tion,  placed  directly  beneath  the  rail,  and  giving  it  a  bearing 
throughout  the  whole  length. 

Longitudinal  bearings  seem  to  possess  no  advantage  over 
cross  ties,  but  are  subject  to  some  decided  disadvantages. 
In  case  of  removal,  two  rails  at  least  must  be  taken  up  to 
admit  of  the  replacing  a  timber ;  while  with  cross  ties  any 
one  may  be  taken  out  and  replaced  without  even  affecting 
the  immediate  passing  of  a  train.  A  continued  bearing  is 
no  better  than  a  broken  one,  as  the  strength  of  the  timber 
itself  offers  very  little  resistance  to  the  weight  of  a  loco 
motive.  Strength  is  not  to  be  expected  in  the  timber-work ; 
it  is  only  the  elastic  medium  between  the  rail  and  the 


274  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

ground  serving  to  maintain  the  rail  in  a  proper  position. 
The  strength  is  in  the  rail.  The  distance  at  which  to  place 
cross  ties  depends  upon  the  weight  of  engines  traversing 
the  road,  the  nature  of  the  ballast,  and  the  strength  of  the 
rail  ;  somewhere  between  two  and  four  feet  from  centre  to 
centre. 

The  amount  of  superficial  bearing  which  the  timber-work 
ought  to  give  per  lineal  foot  of  rail,  is  differently  estimated 
by  different  engineers. 

Upon  the  4'  &¥'  guaged  roads  of  America,  If  square  feet 
per  lineal  foot  of  rail  has  been  allowed. 

Several  of  the  English  roads  give  the  following  :  — 


Name  of  road.  Guage. 

London  and  N.  W.  Railway,  4'  8J"  3 

Great  Western,  7'  0"  2± 

S.  and  W.  of  Ireland,  5'  3"  3f 

Midland  G.  W.  of  Ireland,  5'  3"  2  A 

If  ties  are  made  eight  inches  wide,  and  eight  feet  long  • 
we  have  the  following  amounts  of  bearing  surface  per  lineal 
foot  of  the  rail  with  different  distances  of  the  ties. 

Distance  C  to  C  of  tie.  Superficial  feet  per  lin.  foot. 

2  2.66 
2£  2.13 

3  1.78 
31  1.53 

Of  course  the  longer  the  tie  is  made  the  greater  may  be  the 
distance  between,  provided  the  rail  will  bear  it.  Mr.  Peter 
Barlow,  in  his  report  of  August,  1835,  to  the  directors  of 
the  Liverpool  and  Manchester  Railway,  fixes  the  following 
dimensions  for  superstructure. 


SUPERSTRUCTURE.  275 

Distance  between  insides  of  ties  being 

3'  3' 9"  4'  5'  6' 

WS?££L"'  50  59  61  67  79 

Li^nc°hersail  41  4f  4|  5  5* 

At  the  time  these  dimensions  were  given,  however,  much 
less  weight  was  applied  to  the  rails  than  at  the  present  day. 
As  the  bearing  is  increased,  the  rail  must  become  heavier 
and  more  expensive ;  but  the  number  and  cost  of  the  ties  is 
lessened.  The  report  above  referred  to,  concludes  that  five 
feet  bearings,  involving  heavier  rails,  would  cost  no  more, 
after  the  road  bed  is  consolidated,  than  shorter  ones ;  but 
that  on  embankments  and  soft  subsoils,  it  would  be  at  first 
somewhat  more  expensive. 

285.  The  object  of  the  ballast  is,  first,  to  transfer  the  ap 
plied  load  over  a  large  surface ;  second,  to  hold  the  timber- 
work  in  place,  horizontally ;  and  third,  to  carry  away  the 
rain  water  from  the  superstructure ;  it  also  furnishes  the 
means  of  adjusting  the  timber-work  to  the  proper  position. 
It  should  be  at  least  one  half  way  up  the  depth  of  the  tie, 
and  deep  enough  below  the  under  surface  to  prevent  the 
timber  being  forced  down  by  the  passing  weight.  From 
various  observations  it  appears  that  there  should  be  one 
and  a  half  times  the  depth  of  the  tie  of  ballast,  beneath  the 
under  surface ;  or  the  whole  depth  of  ballast  should  be  from 
two  to  two  and  one  half  times  the  depth  of  tie. 

For  ballast,  broken  stone,  gravel,  or  other  dry,  durable, 
and  porous  material,  is  suitable. 

A  perfectly  inelastic  road  bed  is  not  to  be  desired.  Some 
thing  is  necessary  to  absorb  the  shocks  given  by  the  wheels, 
and  prevent  their  reaction  against  the  machinery.  To  sup 
ply  this  amount  of  elasticity,  and  to  transmit  the  weight 
evenly  to  the  ground,  is  the  duty  of  the  ballast  and  timber- 
work. 


276  HANDBOOK   OF  RAILROAD   CONSTRUCTION.. 

Of  late  years  there  has  been  applied,  in  England,  cast-iron 
hemispherical  bowls,  designed  to  take  the  place  of  both  tie 
and  chair.  Such  answers  very  well  when  there  is  no  lack 
of  ballast,  and  where  wooden  ties  are  worth  from  seventy- 
five  cents  to  one  dollar  each. 


SECTION  OF  THE  KAIL. 

286.  A  good  rail  must  be  able  to  act  as  a  girder,  or  sup 
porter,  between  the  ties,  as  a  lateral  guide  upon  curves; 
and  must  possess  a  top  surface  of  sufficient  hardness  and 
size  to  resist  the  rolling  wear  of  the  wheels. 

Tons  per  mfle. 
(2,240  Ibs.). 

15.72 
31.42 
47.14 
62.84 
78.56 
94.28 
110.00 
124.50 
140.01 
155.57 

Single  line      Double  line 
of  rails.  of  rails. 

Thus,  at  sixty  dollars  per  ton,  each  square  inch  of  section 
costs  $943.20  per  mile,  or  $94,320  per  one  hundred  miles, 
whence  the  necessity  of  rolling  the  rail  to  the  form  which 
shall  give  the  greatest  strength  with  the  least  weight. 

The  sections  most  in  use  in  America  are  shown  in  fig. 
136,  and  137. 


Lbs. 

per  yard. 

One  square  inch 
Two  inches 

of  rail  section 
tt 

weighs, 

H 

9.9 
19.8 

Three  inches 

u 

tt 

29.7 

Four  inches 

it 

(( 

39.6 

Five  inches 

u 

tt 

49.5 

Six  inches 

n 

tt 

59.4 

Seven  inches 

tt 

It 

69.3 

Eight  inches 
Nine  inches 

u 

it 

tt 
tt 

79.2 
89.1 

Ten  inches 

tt 

tt 

99.0 

SUPERSTRUCTURE. 
Ficr.  1SR 


277 


Fig.  136  gives  the  most  direct  bearing,  is  compact,  and. 
brings  the  fibres  at  top  and  bottom  more  directly  in  oppo 
sition  with  the  compressive  and  extensive  strains.  The  top 
of  the  rail  being  curved  to  a  radius  of  ten  or  twelve  inches-, 
the  load  is  applied  nearly  to  a  single  point ;  whence  the 
whole  resistance  in  fig.  137,  depends  upon  the  lateral  resist 
ance  of  the  piece  abed  to  being  pushed  down. 

An  objection  is  sometimes  made  to  fig.  136,  on  the  ground 
that  it  splits  off  on  the  line  n  n :  this  will  not  be  the  case 
when  the  head  is  joined  to  the  web  by  a  proper  curve,  as  in 

24 


278  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Fie:.  137. 


fig.  136.  This  splitting  oft'  happens  full  as  often  in  fig.  137. 
as  may  be  seen  where  it  is  in  use  ;  and  it  might  be  supposed 
to  act  in  that  manner ;  because  if  the  weight  is  transferred 
at  all  from  the  point  of  application  to  the  web,  it  must  be  in 
the  direction  ef. 

The  rails  in  present  use  upon  our  roads,  weigh  from  fifty 
to  seventy-five  Ibs.  per  lineal  yard ;  and  are  laid  upon  cross 
ties  placed  at  a  distance  of  from  two  and  one  half  to  four 
feet  from  centre  to  centre. 

OP    THE    ACTUAL    DIMENSIONS    OF    RAILS. 

Digesting  carefully  the  results  of  the  experiments  of  Bar 
low,  Fairbairn,  and  Hodgekinson,  and  the  experience  of  Mr. 
W.  B.  Adams,  and  other  English  engineers ;  also  the  con 
clusions  arrived  at  by  the  Berlin  Convention  of  1850, 
appointed  to  determine  the  best  form  of  section,  we  come 
to  the  following  limiting  dimensions. 

THE    HEAD. 

Mr.  Barlow  limits  the  width  of  head  at  two  and  one  half 
inches  as  the  maximum  ;  the  Berlin  Convention,  at  two  and 
one  fourth  inches ;  W.  B.  Adams,  at  two  and  one  half;  and 


SUPERSTRUCTURE.  279 

all  of  the  above  recommend  supporting  the  edges  of  the 
head  well  from  the  rib. 

THE    VERTICAL    RIB. 

The  experiments  of  the  Prussian  engineers  fix  the  thick 
ness  for  a  rail  four  inches  high,  at  one  half  of  an  inch,  and 
a  rail  four  and  one  half  inches  high,  at  0.6  or  T%  inch.  Mr. 
Barlow  makes  it  six  tenths  of  an  inch  for  a  four  and  one 
half  inch  rail,  and  0.75,  or  three  fourths  inch  for  a  rail  four 
and  five  eighths  inches  high,  and  for  four  and  three  fourths 
inches  high,  0.8  eight  tenths  inch. 

THE   BOTTOM   FLANGE. 

The  use  of  this  is  more  for  bearing  and  fastening,  than 
for  supporting  strength.  The  Prussian  engineers  make 
three  and  one  half  inches  an  ample  base  for  a  rail  five  inches 
high.  The  edge  for  one  half  or  three  fourths  of  an  inch, 
should  be  nearly  horizontal,  or  parallel  with  the  base,  to 
allow  the  spike  to  have  a  good  bearing. 

OF    THE    INCLINATION. 

As  the  tread  of  the  wheel  is  conical,  the  top  of  the  rail 
must  be  inclined  to  fit  this  cone,  otherwise  the  wear  will 
come  upon  the  inner  edge  of  the  rail  only.  This  may  be 
done  in  two  ways ;  by  placing  the  rail  base  level,  and  in 
clining  the  vertical  axis  of  the  cross  section  of  the  rail,  and 
making  the  tread  square  with  that  axis ;  or  by  making  the 
rail  section  true,  and  inclining  the  base,  either  by  cutting 
the  tie,  or  by  a  wedge  placed  between  the  rail  and  the  tie. 

OF    THE    HEAD    CURVATURE. 

If  the  top  surface  of  the  rail  were  perfectly  flat,  and  the 


280  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

wheel  tire  does  not  happen  to  fit  it  exactly,  (from  want  of 
the  proper  position  of  the  rail,  by  settling,  or  other  cause,) 
the  wheel  will  bear  entirely  upon  one  edge,  and  would  soon 
destroy  the  rail.  To  remedy  this,  a  slight  convexity  is  given 
to  the  top.  Mr.  Clark  (in  R.  R.  Mach.),  recommends  the 
top  to  be  curved  to  a  radius  of  ten  or  twelve  inches. 

OF    THE    VERTICAL    DEPTH    (HEIGHT)    OF    THE    RAIL. 

Mr.  Barlow's  general  results  are  as  follow :  — 

Distance  from  inside  to  inside  of  tie.  Height  of  rail. 

3'0"  4J" 

3'  9"  4f" 

4'  0"  4£" 

5'  0"  5" 

&  0"  5^" 

In  the  London  edition  (1836)  of  Barlow's  Strength  of 
Materials,  page  402,  in  a  report  to  the  London  and  Bir 
mingham  Railway  Co.,  upon  the  best  form  and  upon  the 
strength  of  rails ;  after  a  carefully  conducted  set  of  exper 
iments,  and  an  elaborate  theoretical  deduction  of  results, 
the  writer  comes  to  the  following  five  sections  of  rails 
possessing  the  maximum  strength,  with  the  least  weight. 

Dimensions.  No.  1.        No.  2.      No.  3.     No.  4.      No.  5. 

Height,  41         4f  4|  5  5& 

Breadth  at  top,  2£         2£  2£  2£  2£ 

Depth  of  top,  11111 

Thickness  of  rib,  0.6        0.75  0.8  0.85  1.0 

Width  of  lower  flange,  l£         lj  l£  If         If 

Depth  of  lower  flange,  1  1  1  l£         1  £ 

Weight  per  yard,  51.4  58.8  61.2  67.4  79 

Distance  C.  to  C.  of  ties,  3'          3'9"  4'  5'          6' 

This  table  shows  the  ratio  of  material  which  should  be 
placed  in  the  top  and  bottom. 


SUPERSTRUCTURE.  281 

With  the  above  dimensions,  and  joining  the  curve  of  the 
head  to  the  rib  at  two  and  one  fourth  inches  from  the  top 
of  the  head,  we  obtain  a  strong  and  well-shaped  rail,  with 
the  least  material  possible.  See  fig.  136. 

As  an  example  of  the  application  of  the  above,  the  table 
below  has  been  formed,  showing  four  standard  forms,  which 
will  be  found  to  unite  all  of  the  requirements  of  good  rails ; 
the  general  form  being  that  of  fig.  136. 


Dimensions.  Tl^e  weight  of  th,  raUbeing.     ^    . 

Width  of  head,  21        2J        21  21 

.    Rad.  of  top,  12        12        12        12 

Height  of  rail,  4          41        4J  4| 

Thickness  of  rib,  0.6       0.6       0.65  0.7 

Breadth  of  base,  31        31        3|  4 

Depth  of  head  at  point  A  B,  21        2£        21  21 

Thickness  at  edge  of  lower  web,        i          2"          i          i 

and  the  following  figures  show  the  weights  which  should  be 
applied  to  differently  spaced  sleepers. 

Distance  n.  f  Weight  of  rail, 

centre  to  centre  of  tie.     P***0*8  clear'     in  Ibs. ,  per  yard, 

1^  feet,  1     feet,  60  Ibs.  per  yard. 


2 

u 

11 

a 

60 

2i 

u 

if 

a 

60 

2i 

A 

2 

M 

60 

2f 

" 

2i 

« 

65 

3 

M 

H 

C{ 

65 

3i 

<< 

2| 

U 

70 

H 

M 

3 

M 

75 

The  amount  of  inclination  or  bevel  to  be  given  to  the 
cross  section  of  the  rail,  depends  directly  upon  the  curve  of 
the  wheel,  and  indirectly  upon  the  gauge  of  the  track.  (See 
Chapter  XIV.  part  2.)  The  radius  of  curvature  being 
averaged  at  2°,  or  2,865  feet, 

24* 


282  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Feet     or     Inches. 

For  the  4'  8J"  gauge  it  should  be  .0017  .020 

-For  the  5'  gauge,  .0017  .020 

For  the  51'  gauge,  .0019  .022 

For  the  6'  gauge,  .0021  .025 

in  the  width  of  the  rail,  or  two  and  one  half  inches. 

The  above  dimensions  embrace  all  of  the  best  results  of 
experiment  and  experience,  and  at  the  same  time  satisfy  the 
conditions  demanded  by  the  mechanical  and  physical  nature 
of  the  material  —  iron. 


CHAIRS  AND  JOINTS. 

287.  The  chairs  most  common  at  present  are  made  of  a 
wrought  iron  plate,  with  two  lips,  either  cut  and  punched 
up,  or  forged  up,  to  hold  the  lower  web  of  the  rail.  Such 
chairs  weigh  from  six  to  ten  pounds  each,  and  are  less  liable 
to  break  than  the  common  form  of  cast-iron  chairs.  It  is 
probable  that  a  cast-iron  chair  may  be  made,  however,  with 
properly  shaped  lips,  and  so  hollowed  out  as  to  be  at  once 
strong  and  light.  (See  Clarke's  R.  R.  Machinery,  "Per 
manent  Way.") 

Of  late  the  chair  of  Mr.  Daniel  L.  Davis,  of  Dedham, 
Mass.,  has  attracted  considerable  attention,  and  bids  fair  to 
be  the  means  of  obtaining  a  better  rail  surface  than  has 
heretofore  been  possible.  This  gentleman  has  been  for 
twenty  years  Road-master  of  the  Boston  and  Providence 
Railroad,  and  has  had  ample  opportunity  for  considering 
the  subject  of  track  laying  in  every  respect.  The  rail  bears 
upon  a  cup  of  wrought  iron,  which  rests  upon  a  piece  of 
rubber,  lying  in  the  chair.  The  testimony  of  the  leading 
managers  of  the  New  England  Railroads  bears  witness  of 
the  excellence  of  the  arrangement. 


SUPERSTRUCTURE.  283 

The  practice  of  notching  each  end  of  the  rail  causes  the 
expansion  to  be  exerted  directly  against  the  fastenings,  which 
should  not  be  the  case.  Some  point  should  be  fixed  longi 
tudinally,  to  resist  the  end  shocks  from  the  wheel.  This 
point  should  be  either  the  centre  or  one  end  of  the  rail.  End 
chairs  may  hold  the  rail  laterally,  and  vertically,  but  not 
longitudinally. 

The  weakest  part  of  the  track  is  that,  where,  to  resist  the 
concussions  of  the  wheels  it  should  be  strongest,  namely, 
at  the  joint :  here  we  lose  the  strength  of  the  rail  and  depend 
entirely  upon  the  tie.  The  flattened  ends  of  rails  which 
have  been  laid  for  a  few  years  show  the  bad  effect  of  the 
common  joint.  The  complete  remedy  for  this  is,  so  splicing 
the  rail  that  it  is  as  strong  at  the  joint  as  elsewhere.  The 
method  termed  "  fishing,"  is  not  much  more  expensive  than 
the  ordinary  method  of  jointing,  it  is  perfectly  effectual,  and 
has  had  the  test  of  long  and  successful  use.  It  consists  in 
bolting  a  plate  two  and  one  half  feet  long,  two  Fig.  m 
and  one  half  or  three  inches  wide,  and  from 
one  third  to  one  half  inch  thick,  to  the  ends 
of  both  rails  making  the  joint;  one  plate 
being  placed  on  each  side.  The  plates  are 
convexed  a  little  from  the  rail  as  in  fig.  138, 
so  that  being  sprung  by  screwing  on  the  nuts, 
the  latter  shall  not  work  loose  by  the  vibration  of  the  rail. 

In  the  above  arrangement  there  is  no  tie  below  the  joint, 
but  the  latter  lies  midway  between  two  sleepers. 

Another  method  of  "fishing "  is,  to  place  a  piece  of  H  or 
T  iron  beneath  the  rail,  bolting  it  firmly  to  the  lower  flanges. 

In  bolting  rails  together  at  the  ends,  the  bolt  holes  must 
be  cut  a  little  larger  than  the  bolt,  to  allow  for  the  expansion 
of  the  iron. 

The  effect -of  the  joint  upon  the  passing  carriage,  is  the 


284  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

jumping  motion ;  the  middle  of  each  rail  being  a  summit, 
and  the  end  a  depression,  (the  strength  at  the  joint  being 
taken  away) ;  and  if  the  joints  are  not  opposite  to  each  other, 
there  is  generated  a  very  injurious  and  dangerous  side 
rocking.  Figs.  138,  138  A,  and  138  B,  show  the  methods 
of  fishing. 

Fie.  UN  A. 


xig.  idd  i>. 


To  avoid  the  wear  caused  by  frequent  joints,  various 
forms  of  compressed  rails  have  been  proposed ;  consisting 
of  two  or  more  parts  breaking  joint.  One  form  has  been 
contrived  in  which  the  section  is  vertically  halved ;  another 
of  three  parts,  a  head  placed  on  top  of  a  double  vertical 
Fig  139  web.  Fig.  139  shows  what  would  seem 

to  answer  any  purpose  (if  compound  rails 
are  at  all  allowable).  The  joint  is  here 
divided  into  four  parts,  so  that  the  strength 
of  the  bar  at  any  point  is  reduced  only 
one  fourth.  In  bolting  the  parts  together 
the  joints  should  be  left  open  enough  (see  in  advance)  to 
allow  for  contraction ;  and  the  bolt-holes,  as  before  noticed, 
should  be  longer  than  the  bolts.  (This  enlargement,  extend 
ing  only  in  the  direction  of  contraction,  and  not  in  the  line 
of  the  force.)  The  upper  part  of  such  a  rail  should  be 


SUPERSTRUCTURE.  285 

hardened  to  resist  the  rolling  of  the  wheels,  while  the  webs 
must  possess  the  strength  to  act  as  a  girder. 

It  is  questionable  whether,  by  dividing  the  rail,  particu 
larly  when  it  is  done  horizontally,  we  do  not  prevent  the 
mutual  extension  and  compressive  actions  which  ought  to 
have  place  in  the  top  and  bottom ;  for  we  cannot  make  the 
bolts  perfectly  tight  because  of  expansion. 

Some  of  the  compressed  rails  which  have  been  laid  in 
America  have  given  good  results,  others  have  not. 

Mr.  W.  B.  Adams  observes,  that  a  compressed  rail  to  be 
as  strong  as  a  sixty  pound  whole  rail,  must  weigh  ninety 
ibs.  per  yard. 

Some  engineers  have  proposed  such  a  rail  that  when  one 
side  becomes  worn  it  may  be  turned  over  so  that  the  lower 
may  become  the  upper  table.  This  is  quite  wrong  in  prin 
ciple;  as  when  the  lower  fibres  have  been  subjected  for 
some  time  to  extension,  they  are  entirely  unfitted  to  oppose 
compression. 

OF   THE    LIFE    OF   RAILS. 

288.  The  time  which  a  rail  will  last,  depends  upon  the 
form  and  weight,  and  on  the  quality  of  the  iron ;  and  upon 
the  number,  weight,  and  speed  of  engines  and  cars  passing 
over  it. 

NOTE.  —  The  effect  of  quality  is  altogether  too  little  regarded  in  America. 
How  worthy  of  attention  it  is  may  be  seen  by  the  following. 

Upon  the  same  road  were  used  two  kinds  of  seventy-two  pound  rails,  each  five 
inches  deep,  and  having  a  bearing  surface  of  2.7  inches  in  width.  The  one  was 
worn  out  with  a  tonnage  of  41,000,000  tons,  the  other  of  22,000,000  tons;  the 
difference  being  entirely  in  the  quality  of  the  iron. 

Upon  the  Philadelphia  and  Reading  Railroad  there  have  been  used  forty-five 
pound  rails  of  reheated  and  refined  iron,  which  have  lasted  for  eighteen  years ; 
and  that  with  a  very  heavy  traffic  upon  them.  While  upon  other  American 
roads,  English  sixty  pound  rails  have  required  renewing  in  one,  two,  three,  and 
four  years. 


286  HANDBOOK   OP   RAILROAD    CONSTRUCTION. 

The  durability  of  rails  is  practically  independent  of  time, 
and  depends  entirely  upon  the  amount  of  work  done.  The 
repairs  of  iron,  depending  upon  flaws  and  other  physical 
defects,  will  be  greater  at  the  commencement  of  operations 
than  afterwards.  After  the  first  one  or  two  years  the  regu 
lar  depreciation  begins.  The  first  Liverpool  and  Manches 
ter  rail  weighed  thirty-five  Ibs.  per  yard,  and  the  locomotive 
seven  and  a  half  tons.  As  the  traffic  increased,  so  did  the 
necessary  weight  of  engines,  and  a  corresponding  increase 
in  the  strength  and  weight  of  rails  was  also  rendered  neces 
sary.  In  1831,  the  average  weight  of  engines  with  tenders 
was  eighteen  tons.  In  1855,  the  maximum  engine  with 
tender,  fuel,  and  water  weighed  sixty  tons;  and  in  like 
manner  the  rails  increased  from  thirty-five  to  eighty-five  Ibs. 
per  yard. 

Messrs.  Stephenson  and  Locke,  in  a  report  to  the  Lon 
don  and  North-western  Railroad  Company,  in  1849,  recom 
mend  the  adoption  in  future  of  an  eighty -five  Ib.  rail. 

Upon  the  roads  of  Belgium  are  used  rails  of  fifty-five 
and  sixty-four  Ibs.  per  yard ;  but  it  is  asserted  that  an  eighty 
Ib.  rail  would  allow  of  ten  times  more  traffic. 

For  the  average  of  American  roads,  when  the  iron  is 
good,  (in  quality^)  fifty-five,  sixty,  and  at  most  sixty-five  Ibs., 
will  probably  be  found  ample  for  the  heaviest  traffic :  the 
rail  being  of  the  form  already  given,  and  supported  on 
ties  not  more  than  two  and  a  half  feet  from  centre  to 
centre. 

Mr.  Belpaire,  (of  the  Belgium  engineers,)  concludes,  from 
many  experiments,  that  in  sixty  miles,  each  engine  abrades 
2.2  Ibs. ;  each  empty  car  4i  pz. ;  and  each  ton  of  load 
1.4  oz. ;  the  amounts  being  in  direct  ratio  to  the  several 
weights. 

Captain  Huish,  of  the  London  and  North-western  Rail 
road,  (England,)  estimates  (Report  of  April,  1849)  that  fifty 


SUPERSTRUCTURE.  287 

trains  per  day,  or  18,250  trains  per  annum,  for  twenty  years, 
would  wear  out  a  seventy  Ib.  rail. 

The  Belgian  engineers  have  concluded  that  3,000  trains 
per  annum,  for  one  hundred  and  twenty  years,  would  wear 
out  a  fifty-five  Ib.  rail. 

Now  120  X  3,000  =  360,000  Belgian,  and  20  X  18,250  = 
365,000  English,  a  very  satisfactory  coincidence,  as  the  dif 
ferent  observers  did  not  know  of  each  other's  proceedings. 
The  difference,  5,000  trains,  being  accounted  for  by  the  use 
of  heavier  engines  upon  the  roads  of  England. 

From  the  above  results  the  following  table  is  formed, 
showing  the  life  of  rails  under  from  two  to  one  hundred 
trains  per  day.  American  roads  being  less  nicely  finished,  as 
regards  the  road-bed,  will  of  course  wear  out  rails  faster 
than  the  roads  of  Europe.  The  table  will  serve  as  a  base 
for  estimates. 

Trains  per  day.  Trains  per  year.  No.  of  years' life  of  rails. 

2  600  604 

4  1,200  302 

6  1,800  201 

8  2,400  151 

10  3,000  121 

12  3,600  100 

14  4,200  86 

16  4,800  75 

18  5,400  67 

20  6,000  60 

30  9,000  40 

40  12,000  30 

60  18,000  20 

80  24,000  15 

100  30,000  12 

Probably  one  half  of  the  above  numbers  of  years  would 
show  the  full  life  of  rails  upon  American  roads. 


288  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

As  those  rails  which  are  most  used  wear  out  the  soonest, 
they  should  be  made  accordingly  heavier.  Such  are  thone 
at  depot  grounds  and  at  sidings. 

NOTE. — From  the  reports  of  the  Reading  (Penn.)  Railroad  it  appears  that  in 
1846  ^{j§  of  the  damaged  rails  were  split;  and  that  in  1845  |-f|-  were  split. 

As  regards  the  quality  of  railroad  iron,  it  is  generally  notoriously  bad,  and  its 
makers  know  it  as  well  as  those  who  buy  it.  Railroad  companies  are  not  willing 
to  pay  for  good  iron.  Comparisons  between  American  and  English  iron  amount 
to  little.  First  rate  iron  can  be  made  in  England  or  in  America,  and  so  can  that 
which  will  last  about  two  years.  Time  will  convince  companies  that  the  most 
expensive  iron  is  the  cheapest. 

TABLE    OF    THE    WEIGHT    PER    MILE    OF    DIFFERENT    RAILS. 

Weight  in  Ibs.  per  yard.  T°(^\^  ^'^iS)' 

50  44.00  39.29 

55  48.00  43.21 

60  52.80  47.19 

62  54.56  48.71 

64  56.32  50.28 

66  58.05  51.86 

68  5U.84  53.43 

70  61.60  55.00 

72  63.36  56.57 

74  65.12  58.14 

76  66.88  59.71 

78  .     68.64  61.28 

80  70.40  62.86 

TRACK-LAYING. 

289.  As  wrought  iron  expands  0.0000068  of  its  length 
per  degree  (Fahrenheit)  of  heat,  a  change  of  130°  will  cause 
the  following  expansions :  — 

In  a  15  feet  rail  .0135  ft. 
«  18  "  "  .0162  « 
«  20  "  "  .0176  " 


SUPERSTRUCTURE. 


289 


and  that  the  track  may  be  kept  in  the  right  vertical  and 
horizontal  line,  rails  laid  in  cold  weather  must  not  be  placed 
in  contact ;  but  separated  by  space  enough  to  allow  expan 
sion  to  take  place.  In  hot  weather  they  may  be  placed 
close  together.  Calling  100°  the  maximum  and  — 30°  the 
minimum,  we  form  the  following  table  for  the  average 
lengths  of  rail,  (20  feet). 

At  —  30°  place  the  rails  in  contact. 


—  10° 
0° 
10° 
20° 
30° 
40° 
50° 
60° 
70° 
80° 
90° 
100° 


The  proper  distance 
of  rails  may  be  fixed 
by  the  use  of  the  steel 
plates  shown  in  figs. 
140  and  140  A,  which 
are  marked  with  the 
temperature,  accord 
ing  to  their  thickness, 
as  in  the  above  table. 

To  incline  the  rail 
base  may  be  used, 
when  the  rail  is  not 
levelled,  wedges  one 


.00136  feet  .01  6  inches. 

.00272  " 

.032 

u 

.00408  " 

.049 

« 

.00544  " 

.065 

u 

.00680  « 

.082 

a 

.00816  " 

.092 

a 

.00952  « 

.114 

« 

.01088  " 

.131 

ti 

.01224  " 

.147 

" 

.01360  « 

.163 

« 

.01496  « 

.179 

(C 

.01632  « 

.196 

K 

.01768  « 

.212 

u 

Fig.  140. 


290 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  140  A. 


foot  long  and  six  inches 
wide,  spiked  with  the 
rail  to  the  tie.  When 
the  chairs  are  of  cast- 
iron,  they  may  be  cast 
to  the  required  slope. 


FROGS. 

290.   When  one  line  of 
rail    crosses   another,   a 
contrivance  called  a  frog  is  used ;  see  figs.  141  and  142. 

Fig.  141. 


That  the  wheel  may  run  smoothly  from  a  to  c,  fig.  141, 
the  rail  bf  must  be  cut  at  D,  and  the  rail  a  c  must  be  cut 
at  the  same  point.  Cutting  the  two  gives  the  form  shown 
in  the  figure,  and  further  developed  in  fig.  142. 

In  order  that  the  flange  of  the  wheel  shall  not  leave  the 
line  a  c,  when  at  the  break  D,  the  guard  rail  m  m  is  used  to 
confine  the  opposite  wheel.  It  should  be  placed  at  a  dis 
tance  of  two  inches  from,  and  parallel  with,  the  main  rail 
gg,  from  opposite  six  inches  below  the  frog  point  at  s,  to 
six  inches  above  the  shoulder  at  s'.  From  the  ends  of  the 
parallel  line  n  n  the  guard  rail  should  gently  curve  away  at 
both  ends.  Thus  the  wheel  will  be  gradually  brought  into 
the  right  line,  kept  so  until  the  break  in  the  rail  is  passed, 


SUPERSTRUCTURE. 


291 


and  finally  easily 
released.  To  place 
and  maintain  the 
guard  rail  in  the 
right  position,  it  is 
well  to  put  both  it 
and  the  main  rail 
into  a  double  chair, 
which  is  spiked  to 
the  sleeper. 

The  form  and 
dimensions  of  the 
cast-iron  frog  de 
pends  upon  the 
angle  at  which  the 
cutting  rails  cross, 
and  upon  the  size 
of  the  wheel  tire. 

To  draw  the 
frog,  proceed  as 
follows :  — 

Let  a  c  b  be  the 
angle.  Parallel 
with  and  two 
inches  from  b  c 
draw  de,  e  being 
in  a  c  produced. 
In  the  same  man 
lier  fix  the  point  g. 
At  the  width  of 
the  rail  head  (from 
2i  to  2i  inches) 
draw,  parallel  to 
ac,4.  8.  The  point 


Fig.  142 


292  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Pig.  142  A. 


8  is  the  limit  to  the  solid  steel.  At  double  the  rail  width, 
or  4i  inches,  draw,  also,  parallel  to  a  c,  16.  6  ;  5.  6  is  the  limit 
of  the  flat  steel,  generally  about  half  an  inch  in  thickness. 
This  is  the  least  amount  of  steel  allowable ;  it  is  best  to 
steel  the  whole  tongue,  and  all  of  that  part  of  the  wings 
acted  upon  by  the  wheels.  The  geometric  point  is  gener 
ally  very  thin,  and  is  omitted  to  a  distance  far  enough 
back  to  make  the  point  a  third  or  half  an  inch  wide, 
which  is  rounded  off;  eh  and  dk  are  made  two  and  a 
half  inches;  as  also  fm  and  gn\  A;  10  and  mil  are  made 
six  or  seven  inches,  and  joined  to  d  and  f  by  a  curve, 
abrupt  at  first,  but  afterwards  more  gentle.  The  dis 
tances,  5  a  and  6  b  must  be  such  that  a  9  is  three  and  one 
eighth  inches,  -(depending  upon  the  breadth  of  rail  base,) 
o  m"  is  from  three  to  four  inches.  At  the  other  end  of  the 
frog  e  h  must  be  enough  to  make  s  t  at  least  an  inch,  when 
e h  and  ig  are  from  three  to  four  inches;  imf  being,  as  at 


SUPERSTRUCTURE.  203 

the  other  end,  three  or  four  inches.  The  steel  plates  N  N 
are  one  half  inch  in  thickness.  The  surface,  N,  is  two 
inches  above  the  bottom,  M.  The  lower  plate,  M,  is  two 
inches  thick.  A  B,  CD,  and  E  F  are  six  or  seven  inches 
wide,  and  one  inch  thick.  The  spike  holes  \^  square,  the 
spike  being  one  half  inch.  The  sharp  edges,  i^^e/i,  b  £,  8,  9, 
A  s  79,  should  be  rounded  oft  to  fit  the  wheel  at  A,  fig. 
142  A.  The  surface  of  the  tongue  N  9  should  be  formed  to 
a  double  incline  to  fit  the  wheel  cone. 

NOTE.  — Fig.  142  A  gives  the  shape  and  dimensions  of  the  largest  tires. 

Another  method  of  making  a  frog  is  to  cut  and  weld  the 
rails  a  and  b  of  the  track,  as  in  fig.  143.  The  continuations 
of  these  rails  are  bent  as  shown  in  the  figure. 

Fig,  143. 


The  whole  angle  is  placed  upon  a  firm  wooden  bearing* 
There  is  no  weaker  part  of  the  track  than  the  frog.     To 
make  up  the  strength  at  such  places  a  heavy  longitudinal 
timber  twelve  feet  long  will  answer  a  good  end. 

25* 


094 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  1M. 


SWITCHES. 

291.  The  object  of  the  switch 
is  to  adjust  a  single  line  of 
rails  to  two  or  more  pairs, 
so  that  any  two  lines  may  be 
made  continuous.  The  form  in 
general  use  consists  of  two  rails, 
as  at  a  &,  a  b,  fig.  144,  mov 
ing  upon  a  and  a  as  centres. 
Here  the  tangent  point  of  the 
turnout  curve  is  at  c.  The  data 
given  for  the  switch  are  the 
length  of  switch  rail  and  the 
motion  at  the  toe  (c)  (which 
determine  the  direction  of  the 
starting  tangent)  and  the  radius 
of  curvature  of  the  turnout 
curve.  The  required  "  elements 
are,  the  angle  of  frog  at  b  and 
the  distance  from  a  to  the  point 
of  the  frog. 

The  following  formula  and 
table  are  by  Josiah  Hunt,  Esq., 
(at  present  chief  engineer  of  the 
Hannibal  and  St.  Joseph  Rail 
road,  Mo.).  The  formula  was 
first  published  in  Appleton's  Me 
chanics'  Magazine,  vol.  1,  p.  575. 

cot.  S  X  cot.  F 


Where  S=  angle  of  switch. 
F=  angle  of  frog. 
s  =  the  movement. 
ff  =  ihe  gauge. 


SUPERSTRUCTURE. 


295 


Example.  —  How  far  from  the  toe  of  the  switch  is  the 
point  of  the  frog,  the  gauge  being  4'  8i">  the  rail  twenty 
feet  long,  and  moving  five  inches  ;  tke  frog  being  six  feet 
long,  six  inches  wide  across  the  head,  and  three  inches  at 
the  mouth? 

We  have 


240 


72 


=  »(4.708-.417)  X 


6  +  3 


or 


A  Q  \/ 


=  8.582  X  TeHPo  ==*  $&8§  feet. 

4o  -f-  o 


In  laying  the  rails,  the  distance  from  the  point  to  the  end 
of  the  frog  (towards  the  switch)  is  to  be  taken  from  the 
above. 

Table  showing  the  distance  between  the  frog  and  switch, 
gauge  4'  8J",  movement  of  switch-rail  five  inches.  Frog 
six  inches  across  head,  and  three  inches  at  mouth.  Main 
track  being  straight. 


LENGTH  OF  .SWITCH  KAIL. 

Length 

of  frog. 

12 

14 

16 

18 

20 

22 

3 

29.1 

29.7 

30.1 

30.4 

30.7 

30.9 

s£ 

33.3 

34.0 

34.5 

35.0 

35.3 

35.6 

4 

37.3 

38.2 

38.8 

39.4 

39.8 

40.2 

*i 

41.1 

42.2 

43.0 

43.7 

44.3 

44.7 

5 

44.8 

46.1 

47.1 

47.9 

48.5 

49.1 

4 

48.3 

49.8 

51.0 

51.9 

52.7 

53.2 

6 

51.7 

53.4 

54.8 

55.9 

56.8 

57.6 

6£ 

55.0 

56.9 

58.5 

59.8 

60.8 

61.7 

7 

58.1 

60.3 

62.1 

63.4 

64.7 

65.7 

n 

61.2 

63.6 

65.6 

67.2 

68.5 

69.6 

292.  When  the  switch  rail  is  short,  the  angle  between  the 
main  line  and  the  switch  rail,  when  switched,  is  consider 
able  ;  and  causes  quite  a  shock  to  the  passing  engine.  The 
switch  shown  in  fig.  .145  remedies  th  evil,  makes  the  ma- 


296 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


Fig.  145. 


chinery  compact,  and  the  calcula 
tion  simple.  The  tangent  point  of 
the  turnout  curve  is  at  n  n  (the 
usual  heel).  In  place  of  adjust 
ing  the  single  to  the  double  line  of 
rails,  the  double  is  adjusted  to  the 
single  line.  The  data  given  are 
the  gauge  and  radius  of  curve ; 
and,  as  before,  the  elements  re 
quired  the  frog  angle  and  distance 
from  switch  to  frog  point. 
Now 


Rad.2  —  Rad.  less  gauge 2  =  distance 2 , 


&nd  D=y#2— (£—£)*. 

The  angle  of  frog  is  also 

Sin  90  log  D 
Sin  angle  ot  frog  =  — 


The  length  of  this  switch  rail  depends  upon  the  radius  of 
curvature.  The  distance  between  the  two  rails  at  S  must 
be  enough  to  admit  the  wheel  flange,  that  is,  at  least  two 
inches. 

Let  A  B,  fig.  146,  be  the  straight  rail ;  E  D  the  curved 
one.  Draw  G  H  parallel  with  and  two  inches  distant  from 
the  inner  edge  of  A  B.  No  point  of  the  curved  rail  must 
fall  within  G  H ;  whence  E  is  the  turning-point,  and  E  D 
the  length,  found  as  follows. 

Let  R  equal  the  radius  of  curve  to  outside  of  outer  rail ; 
d  equal  two  inches  plus  width  of  rail,  or  i  e,  and  D  equal 
DE. 


SUPERSTRUCTURE. 


297 


Fig.  146. 


Then 


Example.  —  Let  the  radius  of  outer  rail  be  five  hundred 
feet,  and  the  gauge  five  feet.     We  have,  then,  the  distance 


(A.)         D  =    SOO  2  —  495 2  —  72  feet,  very  nearly. 


(B.) 

and  the  length  of  switch 
(C.) 


Sin  90  log  72 
°r       log50(T~  =  8    17' 


y/500 2—  499.65  *=  18|  feet  nearly. 

Five  hundred  feet  is,  therefore,  about  the  longest  radius 
for  which  such  switches  should  be  used. 


298  HANDBOOK   OF  RAILROAJ)   CONSTRUCTION. 

Crossings  occur  where  two  tracks  cross,  and  consist  of 
four  frogs,  with  the  corresponding  guard  rails,  as  in  fig.  147. 


Fig.    147. 


ELEVATION  OF   THE  EXTERIOR  RAIL. 

293.    The  motion  of  a  train  of  cars  around  a  curve  is 
accompanied  by  a  tangential  force,  depending  in  amount 


SUPERSTRUCTURE. 


299 


upon  the  velocity  of  the  train  and  the  radius  of  curvature. 
This  force  tends  to  throw  the  cars  from  the  track ;  and  is 
counteracted  by  elevating  the  exterior  rail. 

The  centrifugal  force  of  any  body  in  motion  in  a  curved 
line  is  shown  by  the  formula 

JFF2 


Kg.  148. 


32  R' 

"Where  W  is  the  weight  in  Ibs. 

Vthe  velocity  in  feet  per  second. 
R  the  radius  of  curvature, 
and  32  the  accelerating  force  of  gravity. 

The  force  tending  to  throw  the  car  from  the  rail  is  not 
centrifugal  but  tangential,  but  it  matters  not  whether  the 
body  is  kept  in  position  by  tension  upon  the  inside  or  by 
compression  on  the  outside ;  the  amount  of  the  force  is  the 
same. 

The  horizontal  pro 
jection  of  the  centre  of 
gravity  of  the  car,  when 
at  rest,  is  at  c,  fig.  148, 
and  when  in  motion 
the  direction  of  the 
weight  should  be  a  b ; 
and  the  inclination, 
c'  a'  b',  must  be  such 
that  a  b  will  be  perpen 
dicular  to  c'a']  to  effect 
which,  c'b'  should  be 
to  a' b'  as  the  weight 
to  the  tangential  force ;  or  E  being  the  elevation  of  the 
rail,  g  the  gauge,  TFthe  weight,  and  c  the  tangential  force; 

we  have 

E-.giic:  W, 


300 


HANDBOOK   OF  RAILROAD   CQNSTRUCTION. 

CI 
W 


eg  WVZ 

or  E  =  j= ,  and  c  being  = 


32 


finally  j 


W 


Fig.  149.  Where  W=  weight  of  a  car. 

V=  speed  of  train  in  feet  per  second, 
g  =  gauge  of  road. 
JR=.  radius  of  curve. 
JE=  elevation  of  outer  rail  in  feet  and 
decimals. 

g  and  R  are  the  only  fixed  quantities  in 
the  formula  ;  and  the  average  weight  and 
speed  of  a  car  must  be  assumed. 

Examination  of  the  formula  shows  how 
important  it  is  that  all  trains  should  run 
at  such  a  velocity  as  to  demand  the  same 
elevation  of  rail.  The  absolute  elevation 
must  be  arranged  to  meet  the  requirement 
of  the  fastest  trains  *r  and  other  trains  must 
conform,  even  at  a  disadvantage. 

NOTE.  —  The  subject  of  the  mechanics  of  traversing  rail 
road  curves,  is  yet  quite  in  the  dark.  The  action  of  the 
train,  as  caused  by  its  own  momentum,  is  tangential; 
while  the  action  of  the  engine  tends  to  pull  the  cars 
against  the  inner  rail,  being  opposed  to  the  first  motion. 
This  might  require  &  reduction  of  the  elevation  given  by 
the  formula  when  the  engine  is  exerting  a  strong  tractive 
power,  but  when  running  without  steam  the  full  eleva 
tion  is  needed,  (see  chapter  HI.) 

In  laying  and  maintaining  the  rails  to 
the  proper  elevation,  a  clinometer  attached 
to  a  rail  gauge,  as  in  fig.  149,  answers  a 
good  end:  the  small  arc  being  graduated  according  to  the 


SUPERSTRUCTURE. 


301 


different  elevations  required  by  curves  of  different  radii. 
Thus  the  index  of  the  level  being  placed  at  2°,  when  the 
rails  are  fitted  to  A  and  B,  the  elevation  is  correct  for  a  2° 
curve  ;  or  for  a  curve  of  2,865  feet  radius. 

The  difference  in  gauge  of  one  foot  makes  a  difference 
in  the  elevation  of  but  0.009  feet,  or  about  ^  of  an  inch. 

The  following  table  is  calculated  for  the  average  of  the 
different  gauges  in  use,  thus,  — 

4.7 
5.0 
5.5 
6.0 


4)21.2 
Average  gauge,         5.3  feet. 


TABLE  OF  ELEVATION  OP  OUTER  BAIL. 


ELEVATION  OP  OUTER  RAIL  IN  FEET  AND  DECIMALS,  THE 

Badiusof 

VELOCITY  IN  MILES  PER  HOUR  BEING 

curve  in  feet, 

being 

10. 

15. 

20. 

25. 

30. 

40. 

250 

.130 

500 

.070 

1,000 

.037 

..079 

2,000 

.018 

.040 

.074 

.111 

3,000 

.013 

.026 

.048 

.074 

.106 

4,000 

.009 

.020 

.037 

.058 

.079 

.154 

5,000 

.007 

.016 

.031 

.045 

.065 

.119 

6,000 

.006 

.013 

.024 

.037 

.053 

.095 

7,000 

.005 

.011 

.021 

.033 

.046 

.086 

8,000 

.004 

.010 

.018 

.029 

.039 

.077 

10,000 

.003 

.008 

.010 

.022 

.032 

.059 

26 


CHAPTER    XIV 

EQUIPMENT, 


PART  I. 

LOCOMOTIVES. 

As  the  locomotive  engine  is  the  power  by  which  railroads 
are  worked,  and  as  its  proportions  and  dimensions  are  so 
intimately  connected  with  the  physical  character  of  the  road, 
it  is  thought  proper  to  take  space  enough  at  this  point  to 
examine  the  general  principles  of  its  construction,  and  of  its 
adaptation  to  the  work  required  of  it  upon  railroads. 

Under  the  general  principles,  we  recognize  the  production 
and  consumption  of  steam,  the  disposition  of  weight  upon 
the  several  pairs  of  wheels  which  shall  secure  the  necessary 
adhesion,  the  application  of  the  power  generated  in  the 
boiler  to  the  moving  of  the  wheels,  and  that  general  arrange 
ment  of  parts  which  shall  render  the  use  of  power  eco 
nomical. 

BIRTH  AND  GROWTH  OF  THE  LOCOMOTIVE. 

294.  The  first  idea  of  the  application  of  steam  to  loco 
motion,  is  due  to  the  unfortunate  Solomon  de  Caus,  of  Nor- 


EQUIPMENT.  303 

mandy  (France),  who  was  confined  in  a  madhouse  for  in 
sisting  that  steam  could  be  made  to  move  wheeled  carriages. 

295.  In  the  year  1784,  William  Murdoch,  the  friend  and 
assistant  of  James   Watt,  built  a   non-condensing   steam 
locomotive  engine,  on  a  scale  of  about  one  inch  per  foot, 
having 

Cylinders, I  X  2  inches, 

Wheels,  .         .     ,  ...  '     .         .     9£  inches, 

and  Weight,        .  .  10  Ibs. 

This  little  engine,  however,  accomplished  the  speed  of  ten 
miles  per  hour. 

296.  In  1802,   Richard  Trevethick  patented  the  appli 
cation  of  the  non-condensing  steam-engine  to  the  propelling 
of  carriages  on  railroads ;  his  engine  was  fitted  with  one 
horizontal  cylinder,  which  applied  its  power  to  the  wheels 
by  means  of  spur  gear. 

297.  In  1825,  the  truck  was  first  applied,  to  relieve  the 
driving  wheels  of  a  part  of  the  weight,  and  to  enable  the 
engine  to  pass  freely  around  curves. 

298.  In  1827,  Timothy  Hackworth  applied  the  blast  pipe, 
for  the  purpose  of  draft.     He  applied,  also,  spring  balances 
to  the  safety-valves,  and  used  the  waste  steam  to  heat  the 
feed  water.     This  engine  drew  one  hundred  tons,  at  five 
miles  per  hour,  and  forty-five  tons  on  a  fifty  feet  grade. 

299.  In  1828,  M.  Leguire  (France)  introduced  the  mul- 
titubular  boiler. 

300.  In  1829,  the  directors  of  the  Liverpool  and  Man 
chester  Railroad  offered  a  premium  for  the  best  locomotive, 
which  should  draw  three  times  its  own  weight,  at  ten  miles 
miles  per  hour.     The  "  Rocket,"  by  Robert  Stephenson,  of 
Newcastle  on   Tyne,  was  the   successful  competitor,   and 
drew  the  load  required,  seventy  miles,  at  an   average  speed 
of  13.8  miles  per  hour ;  its  maximum  velocity  was  twenty- 


304  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

nine  miles  per  hour;  it  evaporated  5.4  Ibs.  of  water  per 
pound  of  coke,  and  18.24  cubic  feet  per  hour. 

301.  From  1830  to  1840,  the  changes  that  were  made 
were  rather  those  of  dimension,  proportion,  and  arrange 
ment,  than  of  essential  elements  of  steam  producing. 

302.  In  1840,  several  truck  frame  engines  were  sent  to 
England  from  the  Norris  Works  of  Philadelphia.     These 
locomotives  would  draw  a  load  of  one  hundred  and  twenty 
tons  over  a  sixteen  feet  grade,  at  the  rate  of  twenty  miles 
per  hour. 

303.  In  1845,  the  Great  Western  Railroad,  of  England, 
was  supplied  with  an  engine  of  twenty-two  tons  weight, 
having  cylinders  15|  X  18,  wheels  7  feet,  heating  surface 
829  square  feet.     This  locomotive  carried  seventy-six  and 
one  half  tons  at  a  velocity  of  fifty-nine  miles  per  hour.     The 
consumption  of  coke  was  35.3  Ibs.  per  mile,  and  of  water, 
201.5  cubic  feet  per  hour. 


THE  ENGLISH  LOCOMOTIVE  OF  1850. 

304.  The  "  neplus  ultra"  for  the  seven  feet  gauge  (Great 
Western  Railway)  by  Gooch,  has  inside  cylinders  18  x  24 
inches,  one  pair  of  eight  feet  driving  wheels,  grate  area 
twenty-one  square  feet.  Fire-box  surface,  one  hundred  and 
fifty-three  feet.  Three  hundred  and  five  two  inch  tubes,  giving 
1,799  feet  of  surface.  Total  heating  surface,  1,952  square 
feet.  Weight  of  engine,  empty,  thirty-one  tons  ;  of  tender, 
eight  and  one  half  tons  ;  whole  weight  with  wood  and  water, 
fifty  tons.  Evaporating  power,  three  hundred  cubic  feet 
of  water  per  hour.  This  engine  can  draw  two  hundred 
and  thirty-six  tons,  at  forty  miles  per  hour. 

The  maximum  for  the  London  and  North-western  Rail-' 
road,  four  feet,  eight  and  one  half  inches  gauge  (Crampton's 


EQUIPMENT.  305 

patent),  has  cylinders  18x24  inches;  wheels,  eight  feet; 
two  hundred  two  and  three  sixteenths  inch  (outside  diameter) 
tubes ;  grate,  twenty-one  and  one  half  square  feet ;  fire  sur 
face,  one  hundred  and  fifty-four  feet ;  tube  surface,  2,136  feet ; 
whole  heating  surface,  2,290  square  feet ;  weight,  loaded, 
thirty-five  tons ;  twelve  tons  upon  driving  wheels;  tender, 
twenty-one  tons,  loaded  ;  whole  weight,  fifty-six  tons. 


THE  AMERICAN  LOCOMOTIVE  OF   1855. 

305.  The  engine  "  Charles  Ellet,  Jr.,"  drew  on  the  9th  of 
August,  1854,  forty  tons,  over  a  grade  of  two  hundred  and 
seventy-five  feet  per  mile,  and  over  grades  of  two  hundred  and 
thirty-eight  feet,  upon  curves  of  three  hundred  feet  radius. 
This  engine  has  wheels  four  and  one  half  feet  in  diameter 
coupled  seven  feet  apart ;  cylinders  14  X  26  inches ;  and 
weighs,  including  wood  and  water,  53,058  Ibs.  This  is  a 
tank  locomotive,  the  tender  is  dispensed  with,  and  in  its 
room  a  tank  containing  one  hundred  cubic  feet  of  water, 
and  one  cord  of  wood  is  used.  This  engine  was  built  by 
Kiehard  Norris  and  Son. 

An  engine  built  by  the  Cuyahoga  Steam  Furnace  Co.  of 
Cleveland,  Ohio,  performed  the  following  feat. 

An  ordinary  passenger  train  was  carried  one  hundred  and 
one  miles,  over  a  total  ascent  of  1,255  feet  of  grades,  making 
twenty  stops,  at  an  average  speed  of  twenty-five  miles  per 
hour,  with  a  consumption  of  only  ninety  cubic  feet  of 
wood. 

The  same  engine  drew  an  average  load  of  three  and  one 
third  cars  four  hundred  and  thirty  miles,  making  seventy- 
five  stops,  surmounting  a  total  ascent  of  5,439  feet,  averaging 
twenty-five  miles  per  hour,  with  one  tender  full  of  wood 
only, 

26* 


306  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

In  the  months  of  July  and  August,  1856,  two  engines 
upon  the  Pacific  Railroad  (Missouri),  one  by  R.  R.  &  G., 
and  one  by  Palm  &  Robertson,  ran  each  one  hundred  and 
twenty-five  miles,  with  three  passenger  and  one  baggage 
cars,  using  only  one  cord  of  wood. 

NOTE. — For  an  interesting  example  of  what  can  be  done  by  the  American 
locomotive,  and  an  illustration  of  engineering  peculiarly  American,  the  reader 
is  referred  to  a  description  of  the  "  Mountain  top  track  "  at  the  Rock-fish  Gap 
crossing  of  the  Blue  Ridge  (Va.),  by  the  Virginia  Central  Railroad,  given  by 
the  engineer  under  whose  direction  the  work  was  proposed  and  executed 
(Charles  Ellet,  Esq.),  from  which  is  extracted  the*  folio  wing :  — 

"The  eastern  slope  is  12,500  feet  long,  and  rises  610  feet;  the  average  grade 
being  257-^  feet,  and  the  maximum  295^%  feet  per  mile.  The  least  radius  of 
curvature  234  feet;  upon  which  curve  the  grade  is  237 T6<y  feet  per  mile.  The 
western  slope  is  10,650  feet  long,  and  falls  450  feet;  the  average  grade  being 
223^,  and  the  range  279T8n*o  feet  per  mile. 

"  The  engines,  which  have  taken  loads  ranging  from  twenty-five  to  fifty  tons  up 
one  slope  at  seven  and  one  half  miles  per  hour,  and  down  the  opposite  one  at  six 
miles  per  hour,  making  four  trips  of  eight  miles  per  day  for  three  years,  were 
designed  and  built  by  M.  W.  Baldwin  &  Co.,  Philadelphia,  and  have  three  pair 
of  forty-two  inch  wheels  all  coupled,  the  flange  base  being  9'  4",  cylinders 
16^  X  20  inches,  weigh,  with  wood  and  water,  55,000  Ibs.,  or  twenty-seven  and 
one  half  tons.  They  run  without  a  tender,  the  engine  carrying  its  own  feed ; 
thus  gaining  the  double  advantage  of  increasing  the  adhesion  of  the  engine,  and 
avoiding  the  resistance  of  a  tender." 


GENERAL  DESCRIPTION. 

306.  The  locomotive  is  a  non-condensing,  high  pressure 
engine,  working  at  a  greater  or  less  degree  of  expansion, 
according  to  the  labor  to  be  performed,  and  placed  upon 
wheels  which  are  so  connected  with  the  piston,  that  any 
motion  of  the  latter  is  communicated  to  the  former,  by 
which  the  whole  is  moved. 

The  power  exerted  in  the  cylinder  and  referred  to  the 
circumference  of  the  driving  wheel,  is  called  traction;  its 


EQUIPMENT.  307 

amount  depends  upon  the  cylinder  diameter  and  steam  pres 
sure,  upon  the  diameter  of  wheel  and  stroke,  this  latter  being 
the  distance  between  the  wheel  centre  and  point  of  appli 
cation  of  power. 

The  means  by  which  the  "  traction  "  is  rendered  available 
for  moving  the  engine  and  its  load,  is  the  resistance  which 
the  wheel  offers  to  slipping  on  the  rail,  or  its  bite,  and  is^ 
called  adhesion ;  it  is  directly  as  the  weight  applied  to  the 
wheels,  but  depends  also  upon  the  state  of  the  rails.  It 
varies  from  nothing,  when  there  is  ice  on  the  rail,  to  one 
fifth  of  the  weight  upon  the  driving  wheels  when  the  rail  is 
clean  and  dry,  and  in  some  cases  has  reached  as  high  as 
nearly  one  third.  It  should  be  enough  to  resist  the  max 
imum  force  of  traction,  that  is,  the  wheel  should  not  slip 
when  the  engine  is  doing  its  greatest  work. 

Steam  producing,  Traction,  and  Adhesion,  are  the  three 
elements  which  Determine  the  ability  of  an  engine  to  per 
form  work.  The  proportions  and  dimensions  of  the  ma 
chine  depend  upon  the  duty  required  of  it;  sufficient 
adhesion  for  a  required  effect  should  be  obtained  rather  by 
a  proper  distribution,  than  by  increase  of  weight. 

Fig.  150  shows  the  relative  position  of  parts  in  the  loco 
motive  engine  as  at  present  constructed  in  America. 

1  2,  Grate  upon  which  the  fuel  is  placed. 

1234,  Interior  fire-box. 

5  6,  Exterior  fire-box. 

7788,  Shell  of  the  boiler. 

9  9,  Boiler  flues. 

1011121 3,    Exhaust  chamber,  or  smoke  box. 

14,  Steam  dome,  entrance  to  steam  pipe. 

15,  Steam  pipe. 

16,  Piston. 

18,  Piston  rod. 

19,  Connecting  rod. 


308 


HANDBOOK   OF  RAILROAD  CONSTRUCTION. 


Fig.  "5X 


EQUIPMENT.  309 

20,  Crank. 

21,  Driving  wheel. 

22,  Blast  pipe. 

23,  Chimney. 

27  28,  Leading  wheels,  supporting  the  front  end  of  the 

engine,  turning  on  a  swivel,  29. 
30,  "  Blow  off"  safety-valve. 

307.  The  operation  of  generating  and  applying  steam 
for  the  production  of  motion  is  as  follows  :  — 

The  boiler  and  the  space  between  the  two  fire-boxes 
being  filled  with  water,  (high  enough  at  least  to  cover  the 
flues  and  the  top  of  the  inner  box,)  fire  is  applied  to  the  fuel 
placed  upon  the  grate ;  the  heat  which  fills  the  fire-box  and 
tubes,  is  communicated  to  the  water  and  converts  the  same 
to  steam ;  which  entering  the  mouth  of  the  pipe,  15,  flows 
to  the  cylinder,  where  it  forces  the  piston  to  the  end  of  the 
stroke.  This  motion  is  transferred  through  the  connecting 
rods  and  cranks  to  the  wheels,  which  revolving,  move  the 
engine  upon  the  rails.  At  the  same  time  the  eccentrics, 
placed  upon  the  driving  axle,  give  a  motion  to  the  valve 
gear,  and  thence  to  the  valves,  by  which  the  admission  of 
steam  is  stopped  at  the  first  end  of  the  cylinder,  and  com 
menced  at  the  other.  The  volume  of  steam  which  entered 
during  the  first  half  stroke  is  forced  out  of  the  cylinder  by 
the  returning  piston,  up  the  blast  pipe,  and  out  at  the  chim 
ney,  where  a  vacuum  is  produced,  which  can  be  supplied 
with  air  only  from  the  chamber  10 11 12 13 ;  after  a  few 
strokes  the  air  is  exhausted  from  the  chamber,  which  can  be 
refilled  only  by  the  external  air  drawn  through  the  fuel,  fur- 
nace,  and  tubes.  The  more  complete  this  vacuum,  the 
stronger  the  current  of  air  drawn  through  the  fire,  which 
(current)  is  the  draft.  The  admission  of  fresh  air  is  regu 
lated  by  a  damper  placed  at  2.  The  fuel  is  placed  upon 
the  grate  by  means  of  a  door  in  the  rear  of  the  fire-box. 


310  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

The  necessary  height  of  water  is  maintained  in  the  boiler 
by  pumps  worked  by  the  engine,  in  such  a  manner  as  to 
secure  at  all  times  the  proper  supply.  The  proportions  and 
dimensions  of  the  boiler,  the  engine,  and  the  carriage,  with 
the  rules  for  obtaining  the  same  will  be  considered  shortly. 

DUTIES    EXPECTED    OF    LOCOMOTIVE   ENGINES. 

308.  The  work  required  of  any  engine  depends  upon  the 
nature  and  amount  of  traffic,  and  upon  the  physical  char 
acter  of  the  road. 

The  nature  of  the  traffic,  whether  bulky  or  compact,  and 
whether  requiring  quick  or  slow  transport,  determines  some 
what  the  number  and  size  of  the  trains,  and  consequently 
the  number  and  power  of  the  engines. 

A  road  with  steep  grades  and  sharp  curves,  with  the  same 
amount  of  traffic,  will  need  stronger  engines  than  a  road 
with  easy  grades  and  large  curves. 

The  amount  of  motive  power  and  cost  of  working  it,  de 
pends  in  a  great  degree  upon  the  disposition  of  grades  as 
regards  the  direction  of  the  traffic  movement.  The  most 
economically  worked  road  will  be  either  a  level  one,  or  one 
where  the  bulk  of  the  traffic  is  moved  down  hill. 

The  mineral,  commercial,  or  agricultural  nature  of  the 
country,  determines  the  direction  of  the  traffic,  and  the 
physical  nature,  the  arrangement  of  the  grades. 

The  different  kinds  of  labor  required  of  locomotives,  ne 
cessitate  the  employment  of  engines  of  different  proportions  ; 
and  the  different  classes  of  railways,  require  engines  pos 
sessing  different  amounts  of  power. 

309.  The  classification  of  locomotives  should  be  deter 
mined  according  to  the  following  relations. 

Department  depends  upon  commercial  duty. 
Division  depends  upon  character  of  road. 


EQUIPMENT.  311 

Order  depends  upon  weight  of  trains. 
Class  depends  upon  speed  of  trains. 

NOTE.  —  The  general  classification  is  given  at  the  end  of  this  chapter. 

High  rates  of  speed  are  generally  combined  with  light 
loads,  and  heavy  trains  are  required  to  move  at  the  lower 
velocities. 

Great  speeds  require  the  rapid  production  and  consump 
tion  of  a  large  bulk  of  steam  of  but  little  density ;  large 
wheels  and  short  stroke,  that  the  ratio  of  velocities  of  piston 
and  wheel  may  be  as  great  as  possible. 

Heavy  trains  consume  less  steam  by  bulk,  per  mile,  but 
of  a  much  greater  density,  and  combine  a  long  stroke 
with  a  small  wheel,  by  which  great  leverage  is  obtained. 

In  general,  engines  for  winter  use  should  be  heavier  than 
those  for  summer,  upon  the  same  ground,  as  natural  causes 
are  more  liable  to  resist  adhesion  in  the  winter. 

The  locomotive  engine  may  be  so  proportioned  as  to  run 
at  any  speed  from  ten  to  sixty  miles  per  hour,  over  grades 
from  ten  to  two  hundred  feet  per  mile,  and  to  carry  loads 
from  two  hundred  to  two  thousand  tons. 

The  rules  by  which  the  necessary  dimensions  to  perform 
any  required  duty  are  fixed,  depend  upon  the  very  simplest 
mechanical  laws. 

NOTE.  —  The  formulas  expressing  the  most  proper  relations  to  exist  between 
the  several  steam-producing  and  steam-consuming  parts  are  more  reliable  than 
the  assertions  of  any  machinist  in  America,  and  though  taken  from  books,  are 
the  result  of  the  experience  of  the  most  able  and  practical  men  for  twenty  years. 
Operatives  are  too  apt  to  despise  book  knowledge,  forgetting  that  the  very  knowl 
edge  so  despised  is  the  result  of  more  practice  than  a  lifetime  can  afford  them. 
Railroad  managers  are  too  apt  to  receive  as  indisputable,  the  opinions  of  men 
who  are  practical,  simply  because  they  understand  nothing  of  principle. 

Since  the  work  of  D.  K.  Clark  (England)  has  appeared,  any  dimension  from 
the  beginning  to  the  end  of  a  locomotive  may  be  fixed,  to  the  eighth  of  an  inch, 
with  absolute  correctness,  and  there  is  no  excuse  for  departing  from  the  proper 


312  HANDBOOK  OF  RAILROAD   CONSTRUCTION. 

proportions.  It  does  not  follow  that  because  a  locomotive  does  actually  start  off 
and  draw  the  train,  that  it  is  properly  made.  A  race-horse  can  draw  a  plough, 
and  a  yoke  of  oxen  a  "  trotting  buggy,"  but  this  is  by  no  means  the  correct 
adaptation  of  power. 

310.   The   elements   which   govern  the  requirements   of 
power  are 

The  maximum  grades. 
The  weight  of  the  train. 
The  required  speed. 

And  the  elements  which  govern  our  ability  to  produce  the 
power  needed, 

The  grate  area. 

The  heating  surface. 

The  cylinder  diameter. 

The  steam  pressure. 

The  stroke. 

The  diameter  of  wheels. 

The  weight  upon  driving  wheels. 


MECHANICAL  AND  PHYSICAL  PRINCIPLES   GOVERNING  THE 
CONSTRUCTION  OF  THE  LOCOMOTIVE  ENGINE. 

RESISTANCE   TO   THE   MOTION   OP   RAILROAD    TRAINS. 

311.  The  exact  resistance  to  the  motion  of  a  railroad 
train  cannot  be  determined,  as  some  of  the  elements  are  so 
variable;  for  example,  the  state  of  the  weather.  An  ap 
proximate  estimate,  near  enough  for  practice,  is  easily  ob 
tained.  To  arrive  at  correct  data  the  observations  must  be 
made  upon  trains  working  under  the  same  conditions  that 
they  are  subject  to  in  practice. 

The  whole  resistance  is  made  up  of  several  partial  resist 
ances,  some  of  which  are  constant  at  all  speeds,  and  some 
of  which  increase  with  the  velocity. 


EQUIPMENT.  313 

The  engine  and  tender  resistance  is  composed  of  the 
friction  of  pistons,  cross  heads,  slide  valves,  cranks,  eccen 
trics,  pumps,  the  back  pressure  of  the  blast,  and  various 
erratic  movements,  rolling,  twisting,  and  pitching  together 
with  both  wheel  and  axle  friction,  which  is  common  to  the 
engine  and  tender. 

The  atmospheric  resistance  is  not  due  to  the  direct  action 
of  the  air  upon  the  front  and  sides  of  the  train  entirely,  but 
chiefly  to  the  exhausting  action  in  the  rear.  The  train  has, 
as  it  were,  to  pull  along  a  large  column  of  air  like  the 
water  in  the  wake  of  a  ship ;  form  or  amount  of  frontage 
has  little  or  no  effect.  The  resistance  depends  upon  the 
bulk  of  the  train  and  its  velocity.  A  train  with  the  same 
frontage  offers  more  resistance  as  its  bulk  increases. 

Oscillatory  resistance  is  caused  by  irregularities  in  the 
surface  of  the  rails,  and  increases  with  the  velocity,  and 
also  with  increase  of  height  of  the  centre  of  gravity  of  the 
car  or  engine. 

Frictional  resistance  may  be  divided  into  wheel  and  axle 
friction.  That  of  the  axle  is  composed  of  two  parts,  the 
direct  vertical  friction  on  the  journal,  and  the  side  friction 
on  the  collar,  consequent  upon  lateral  motion.  The  vertical 
friction  is  independent  of  the  surface  pressed  or  of  velocity, 
but  is  directly  proportional  to  the  pressure,  and  the  same 
remark  applies  to  that  of  the  collars.  As  the  diameter  of 
wheel  increases,  the  oscillation  is  increased,  the  centre  of 
gravity  being  raised.  The  direct  cause  of  the  vertical  fric 
tion  is  |he  weight  of  the  car  or  engine,  and  of  the  lateral 
irregularities  in  the  surface  of  the  rails,  which  cause  the  car 
to  sway  from  side  to  side.  Wheel  friction  which  acts  be 
tween  the  periphery  of  the  wheel  and  the  surface  of  the 
rail  increases  with  the  load,  and  decreases  as  the  wheel 
diameter  augments. 

27 


314  HANDBOOK  OF  RAILROAD  CONSTRUCTION. 

For  the  total  resistance  to  the  motion  of  a  railroad  train, 
D.  Jt  Clark  gives  the  following  formula  :  — 


Where  R  is  the  resistance  in  Ibs.  per  ton, 
and  V  the  velocity  in  miles  per  hour. 

From  this  expression  we  form  the  following  table  :  — 

Velocity  in  miles  per  hour.  Resistance  in  Ibs.  per  ton. 

10  8,585      ff.fe  <** 

12  8,842 

15  9,315 

20  10,339 

25  11,655 

30  13,263 

40  17,356 

50  22,620 

60  29,052 

100  66,480 

From  a  great  number  of  experiments  made  by  Mr.  Clark, 
the  relative  resistance  to  the  motion  of  inside  and  outside 
connected  engines  is  as  follows  :  — 

Inside  connections         .....         17 
Outside  connections  ......     14 

The  effect  of  curves,  bad  state  of  the  road,  and  adverse 
winds,  amounts  (according  to  the  same  author)  to  the  fol 
lowing  percentages  :  — 

Bad  state  of  the  road  •''."*'•'     .•  '-f  .     :  ^  ;  .        40 

Curves     .....  ."/"     .  .    20 

Strong  head  and  side  winds  .     '  ty*  f  '4f  v  .         20 

In  all  80 


EQUIPMENT.  315 

The  resistance  due  to  grades  depends  entirely  upon  the 
rate  of  incline,  and  is  quite  independent  of  all  other  con 
siderations.  The  relative  effect  of  grades  decreases  with 
the  absolute  increase  of  resistance  on  a  level.  Thus  com 
mon  roads  admit  of  steeper  grades  than  do  railroads,  be 
cause  the  level  resistance  is  much  more  upon  the  former 
than  on  the  latter. 

The  exact  determination  of  the  resistance  due  to  any 
grade  depends  upon  the  very  simple  mechanical  principle, 
regulating  motion  upon  the  inclined  plane.  For  each  foot 
rise  of  grade  per  mile,  the  resistance  per  ton  is 

2240  X 


5280' 
Thus  the  resistance  to  one  ton  upon  a  forty  feet  grade  is 

40 
2240  X          or  17  lbs* 


And  if  we  are  moving  at  thirty  miles  per  hour  the  sum 
of  all  other  resistances  is,  by  the  formula,  or  the  table  at 
the  end  of  Chapter  XIV.,  part  L,  13.3  lbs.  per  ton  ;  whence 
the  whole  resistance  to  the  motion  of  one  ton,  at  thirty 
miles  per  hour,  upon  a  forty  feet  grade,  is 

17  +  13.3  or  30.3  lbs. 

and  one  hundred  tons  would  be  one  hundred  times  as  much. 
Table  1,  at  the  end  of  Chapter  XIV.,  part  L,  gives  the  whole 
resistance  to  the  motion  of  trains  of  from  fifty  to  one  thou 
sand  tons,  moving  at  speeds  varying  from  ten  to  one  hundred 
miles  per  hour,  and  table  2  gives  the  resistance  upon  grades 
from  ten  to  one  hundred  feet  per  mile. 


316  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


TRACTION  AND  ADHESION. 

312.  The  whole  steam  pressure  upon  both  pistons,  refer 
red  by  means  of  the  crank,  connecting,  and  piston  rods,  and 
wheel,  to  the  rail,  is  called  "  traction."  It  is  the  drawing 
power  of  the  engine.  Its  amount  depends  upon  the 
diameter  of  cylinder,  steam  pressure,  stroke,  and  diameter 
of  wheel. 

By  increasing  the  steam  pressure,  we  increase  the  power. 
By  increasing  the  cylinder  diameter,  we  increase  the  power. 
By  increasing  the  stroke,  we  increase  the  power.  By  de 
creasing  the  wheel  diameter,  we  increase  the  power.  And 
by  adjusting  the  dimensions  of  the  above  parts,  we  may 
give  any  desired  amount  of  power  to  the  engine. 

The  formula  expressing  the  tractive  power  of  an  engine, 
of  any  dimensions,  is 


Where  A  =  the  area  of  one  piston. 

P—  the  steam  pressure  in  cylinder  per  square  inch. 

£=the  stroke  in  inches. 

O==  the  circumference  of  the  wheel  in  inches. 

The  formula  is  expressed  verbally  as  follows  :  Double  the 
stroke  and  multiply  it  by  the  total  steam  pressure  on  both 
pistons;  divide  the  product  by  the  circumference  of  the 
driving-wheel  in  inches. 

ADHESION. 

313.  As  observed  on  page  307,  the  adhesion  or  the  bite 
of  the  wheels  upon  the  rail  is,  as  an  average,  from  one  fifth 
to  one  sixth  of  the  weight  ;  one  fifth  when  the  rail  is  in  a 
good  state,  and  less  when  wet  or  greasy  ;  we  cannot  deperfd 
upon  more  than  one  sixth  in  practice.  Therefore,  if  the 


EQUIPMENT.  317 

tractive  power  of  an  engine  is  3,000  Ibs.  we  must,  to  make 
it  available,  place  3,000  X  6  or  18,000  Ibs.  upon  those  wheels 
which  are  connected  with  the  machinery,  (driving  wheels). 


FUEL. 

314.  The  fuels  employed  in  the  locomotive  engine  for 
the  evaporation  of  water  are  wood,  coal,  and  coke.  In 
England  the  latter  is  used  exclusively.  In  America  the 
first  has,  on  account  of  its  cheapness,  been  quite  generally 
adopted ;  but  of  late  railroad  companies  have  been  turning 
their  attention  to  coal  and  coke. 

The  immense  beds  of  coal  distributed  throughout  the 
United  States  will  furnish  fuel  to  railroad  companies 
almost  without  limit.  Its  position  as  well  as  its  amount 
will  render  its  adoption  practicable  in  nearly  all  of  the 
States.  Ohio  alone  contains  more  coal  than  all  of  Great 
Britain.  The  following  table  is  from  the  iron  manufacture 
of  Frederick  Overman. 

Name  of  State.  Area  of  Coal-fields. 

Georgia    ^, »^ *«>{>-   :y»f      .     .- •••„••' »J      150  square  miles. 

Maryland         .         .     ''';>    '•;'*     .     550  "  « 

Alabama      .         .     •  ffa      .     U7Z'      3,400       "  " 

Tennessee 4,300  "  " 

Michigan 5,000  "  " 

Missouri 6,000  "  « 

Indiana 7,700  "  « 

Ohio 11,900  «  " 

Kentucky 13,500  «  « 

Pennsylvania  ....          15,437  "  « 

Virginia 21,195  «  « 

Illinois 44,000  «  « 

In  all 133,132  «  « 

27* 


318 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


315.  The  following  table  (also  from  the  works  of  Over 
man)  gives  the  nature  and  evaporative  power  of  the  differ 
ent  American  coals. 


Name  of  Coal. 

State 
•where 
found. 

Percent 
age  of  car 
bon. 

Steam  of  212° 
evaporated 
per  Ib. 

Quantity  of 
heat  by 
volume. 

Percentage 
of  coke 
by  weight. 

Anthracite. 

Beaver  Meadow, 

Pa. 

88.9 

10.4 

94 

Forest  Improvement, 
Lehigh, 

Pa. 
Pa. 

90.7 
89.1 

10.8 
9.6 

94 
94 

Lackawanna, 

Pa. 

87.7 

10.7 

94 

Coke. 

Midlothian, 

Va. 

10.3 

92 

.66 

Cumberland, 

Md. 

10.3 

92 

.75 

Bituminous. 

Maryland, 

Md. 

73.5 

11.2 

85 

Cumberland, 

Md. 

74.3 

11.0 

85 

Blossburg, 

Pa. 

73.4 

10.9 

85 

.83 

Karthans, 

Pa. 

73.8 

9.8 

85 

.88 

Cambria  County, 
Clover  Hill, 

Pa. 
Va. 

69.4 
56.8 

10.2 

8.5 

85 
85 

.68 

Tippecanoe, 

Va. 

64.6 

8.5 

85 

Pittsburgh, 
Missouri, 

Pa. 
Mo. 

55.0 

8.9 

85 

.68 
.57 

316.  The  employment  of  the  several  varieties  of  wood 
depends  more  upon  the  commercial  than  the  chemical 
character.  The  following  table  shows  the  specific  gravity, 
the  nature  and  the  evaporative  value  of  the  different 
species. 


EQUIPMENT. 


319 


:i 

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irl 


ill 


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O    0    0    H-  >- 


poop      p 

o  03  bi  Oi       ^ 

if".  03  <£>  00          I-" 


OS  O»  m  O4 
•—"  -^J  00  OJ 


«. 

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CO   CO  O 


OOOOO        OOOOi-i 


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3  J 

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Fg 

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•  a  g, 


!! 


Of  the  relative  value  of  wood  and  coal,  we  have  the  fol 
lowing  results  of  experience. 

In  the  engines  of  the  Baltimore  and  Ohio  Railroad  2.55 
Ibs.  of  pine  wood  were  found  equal  to  one  pound  of  Cum 
berland  coal. 


320 


HANDBOOK   OP  RAILROAD   CONSTRUCTION. 


On  the  Reading  Railroad,  three  pounds  (Pennsylvania) 
of  pine  wood  equal  to  one  pound  of  Anthracite  coal. 

Mr.  Haswell  estimates  the  best  varieties  of  wood  fuel  to 
contain  twenty  per  cent,  of  carbon. 

Walter  R.  Johnson  found  that  one  pound  of  wood,  upon 
an  average,  evaporated  two  and  one  half  pounds  of  water. 

The  average  percentage  of  coak  from  American  bitumi 
nous  coal  from  the  above  table  is  seventy-three  per  cent., 
and  the  average  percentage  of  carbon,  sixty-seven  and  one 
half  per  cent. 

317.  The  following  table  shows  the  relative  properties 
of  good  coke,  coal,  and  wood. 


11 
fi 


s 

•3V  J 


ill 


Coke. 
Coal. 
Wood. 


03 

80 
30 


4300 
4000 
2800 


95 

88 
20 


80 

44 

107 


28 
51 
21 


22.4 
32.0 
16.0 


13 
10 
60 


100 
71 
29 


The  power  of  fuel  depends  upon  the  amount  of  carbon 
in  it. 

Pure  coke  is  solid  carbon. 

Hence  its  superior  value  as  a  heat  generator. 


OF    THE    PROCESS    OF    COKING. 

318.  Anthracite  coal  is  used  for  locomotive  fuel  in  its 
natural  state.  It  is  employed  chiefly  upon  those  roads  on 
the  eastern  slope  of  the  Alleghanies.  The  bituminous  coal 
lies  in  the  Mississippi  valley,  and  may  be  found  anywhere 
between  the  summits  of  the  Alleghanies  and  the  Rocky 


EQUIPMENT.  321 

Mountains.  This,  in  its  natural  state,  contains  so  much 
pitchy  matter  as  to  render  it  unfit  for  locomotive  purposes. 
Upon  being  heated,  it  melts,  runs  into  a  mass,  and  clogs 
the  grate;  requiring  frequent  poking  and  a  strong  draft. 
But  when  the  bitumen  is  burnt  off  by  slow  and  careful 
baking,  (as  described  below,)  no  fuel  equals  it. 

Just  as  carbonized  wood  is  charcoal,  so  carbonized  coal 
is  coke.  Coke  is  bituminous  coal  deprived  of  its  bitumen, 
the  raw.coal  being  baked  in  ovens  having  vents  so  regulated 
as  to  admit  air  enough  to  char,  without  consuming  the  coal. 
The  ovens  being  closed  at  the  proper  time,  the  fire  is  grad 
ually  extinguished,  and  the  coke,  compacted  into  large 
masses,  requiring  to  be  broken  up  before  taken  out.  Coal 
may  be  coked  by  piling  loosely  in  heaps,  covering  with 
earth,  and  firing  through  openings,  which,  after  forty  or 
fifty  hours,  are  closed.  In  preparing  coke,  however,  in  the 
large  quantities  required  for  railroads,  and  that  it  may  be  of 
the  very  best  quality,  a  good  deal  of  care  must  be  taken. 

Probably  in  no  place  more  or  better  coke  is  made,  or  the 
operation  more  skilfully  carried  on,  than  at  the  Camden- 
town  station  of  the  London  and  North-western  Railroad, 
(England). 

The  company  have  built  eighteen  ovens,  in  two  rows,  all 
discharging  their  volatile  gases  into  a  horizontal  flue  termi 
nating  in  a  chimney  one  hundred  and  fifteen  feet  high ;  having 
an  internal  diameter  of  eleven  feet,  and  being  three  feet 
thick,  (making  the  external  diameter  seventeen  feet).  The 
ovens  are  elliptical,  11  X  12  feet  inside,  with  walls  three 
feet  thick.  The  height  is  ten  feet,  the  first  three  feet  from 
the  ground  being  solid,  and  furnished  with  a  fire  brick  floor, 
on  which  the  coal  is  placed.  Each  oven  communicates 
with  the  flue  by  an  opening  in  the  top  two  and  one  half 
feet  by  twenty-one  inches ;  which  opening  is  closed  by  an 
iron  damper,  to  regulate  the  draft.  The  openings  for  the 


322  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

doors  are  three  and  one  half  feet  square  outside,  and  two 
and  three  fourths  inside,  being  closed  with  iron  doors  four 
and  one  half  by  five  feet,  lined  with  fire  brick,  and  balanced 
in  opening  by  counterweights.  (The  object  of  the  chim 
ney  and  horizontal  flue  is  to  carry  the  smoke  and  unburned 
gases  so  far  up  that  they  shall  not  be  a  nuisance.  In 
America  we  might  allow  the  smoke  of  each  oven  to  escape 
through  a  low  chimney  of  its  own,  (ten  or  twelve  feet  high,) 
and  save  the  cost  of  a  large  stack ;  like  the  coking  ovens  in 
our  foundries). 

The  operation  of  coking  is  carried  on  as  follows  :  —  Each 
alternate  oven  is  charged  between  eight  and  ten  A.  M.  every 
day,  with  three  and  one  half  tons  of  good  coals.  A  whisp 
of  straw  is  then  thrown  in,  which  takes  fire  from  radiation 
from  the  top,  and  inflames  the  smoke  then  arising  from  the 
surface,  by  the  reaction  of  the  hot  sides  and  bottom  upon 
the  body  of  the  fuel.  In  this  way  the  smoke  is  consumed 
at  the  very  point  of  the  process,  where  it  would  otherwise 
be  the  most  abundant.  The  coking  process  is  a  complete 
combustion  of  the  volatile  principles  of  the  coal.  The  mass 
of  coal  being  first  kindled  at  the  surface,  where  it  is  supplied 
with  an  abundance  of  oxygen,  because  the  doors  in  front 
and  vents  in  the  rear  are  open,  no  more  smoke  goes  from 
the  chimney  than  from  that  of  a  common  kitchen  fire.  The 
gas  generated  from  the  slightly  heated  coal  cannot  escape 
destruction  in  passing  up  to  the  bright  flame  of  the  oven. 
Any  deficiency  in  oxygen  for  consuming  the  smoke  is  sup 
plied  by  the  air  entering  the  grooves  of  the  dampers. 

As  the  coking  process  advances  most  slowly  from  the  top 
to  the  bottom,  only  one  layer  is  consumed  at  a  time ;  while 
the  surface  is  covered  with  red-hot  cinders,  ready  to  con 
sume  any  particles  of  carburetted  or  sulphuretted  hydrogen 
gases  which  may  escape  from  below.  The  greatest  mass 
cannot  emit  more  gases  than  the  smallest  heap. 


EQUIPMENT.  323 

The  coke  being  perfectly  freed  from  all  smoky  and  volatile 
matters,  by  a  calcination  of  forty  hours,  is  cooled ;  down  to 
a  moderate  ignition  by  sliding  in  the  dampers  and  opening 
the  doors,  which  had  been  partly  closed  during  the  latter 
part  of  the  operation. 

The  coal  is  now  converted  into  a  clean,  crystalline,  po 
rous,  columnar  mass,  of  a  steel-gray  color,  and  so  hard  as  to 
cut  glass.  This  is  broken  up  and  taken  out  —  coke.  It  is 
sometimes  extinguished  by  a  watering-pot.  This  is  wrong, 
it  ought  not  to  be  wet,  and  even  more,  ought  to  be  imme 
diately  shut  up  in  fire-proof  boxes  and  bins.  Even  left  to 
itself  in  the  air,  it  absorbs  moisture  rapidly,  which  must  be 
burned  off  in  the  boiler ;  it  should  by  all  means  be  kept  in 
a  dry  place.  Mr.  Woods  (England)  observes,  that  coke 
may  absorb  as  much  as  eight  per  cent,  of  water  in  going 
from  the  oven  to  the  storehouse.  The  amount  of  absorption 
depends  upon  the  nature  of  the  coke.  D.  K.  Clark  records 
the  following,  the  coke  being  immersed  in  water. 

No.  1.    Close-grained  and  good,  absorbed  14.5  per  cent,  of  water. 
No.  2.   Porous  and  ordinary,  absorbed  21  per  cent. 
No.  3.   Very  close-grained  and  good,  9  per  cent. 

The  time  of  coking  may  be  stated  generally  as  fifty  hours, 
though  it  is  somewhat  improved  by  being  allowed  forty 
hours  more ;  this  gives  time  for  a  better  consolidation,  and 
gives  a  firmer,  brighter,  and  more  crystalline  mass. 

Mr.  Gooch,  of  the  Great  Western  (England)  Railroad, 
experimented  upon  the  time  of  coking  with  the  following 
results. 

•  TT,  o«T  Yield  Per  *°n  Water  evaporated          B0.,,if  * 

of  coal.  per  Ib.  of  coke. 

48  hours  12.71  cwt.  7.1  Ibs.  902. 

72     «  12.00  cwt.  7.7  Ibs.  924. 

Thus,  though  the  yield  per  ton  is  decreased  by  a  greater 


324  HANDBOOK   OP  EATLROAD   CONSTRUCTION. 

time,  the  value  of  the  coke  per  pound  is  augmented,  and 
the  increase  overbalances  the  decrease. 

Firstrate  coal  gives  from  seventy-five  to  eighty  per  cent, 
by  weight,  of  compact  glistening  coke,  weighing  about 
14  cwt.  per  chaldron,  (thirty-six  bushels).  The  bulk  is  in 
creased  from  ten  to  fifty  per  cent. 

In  breaking  out  the  coke  from  the  ovens,  a  great  deal  is 
unavoidably  reduced  too  fine  for  use  in  the  locomotive  fur 
nace  under  a  strong  draft ;  such  may,  however,  be  used  in 
firing  up,  in  standing  still,  and  at  the  stations. 

In  taking  the  coke  from  the  ovens  it  should  be  separated 
into  the  three  following  classes. 

Large  coke.         Cubes  of  9  inches  to  the  side. 
Medium  coke.  "       6      " .  " 

Small  coke.  «       3      "  " 

Pittsburgh  coal  carefully  coked  for  forty-eight  hours,  gives 
seventy -five  per  cent,,  by  weight,  and  one  hundred  twenty- 
five  per  cent,  by  bulk,  of  firstrate,  firm,  bright,  clean  coke. 

The  best  test  for  coke  is  to  place  it  in  water.  Water, 
weighing  sixty-two  and  one  half  pounds  per  cubic  foot, 
should  not  float  good  coke,  which  ought  to  weigh  sixty- 
three  pounds  per  cubic  foot,  therefore  if  the  coke  floats  it  is 
too  light. 

Much  of  the  bituminous  coal  in  the  Mississippi  valley 
does  not  coke,  but  burns  up.  A  large  part  cokes  moderately 
well,  but  not  so  well  as  the  Pittsburgh  coal.  In  estimating 
for  a  comparison  of  fuels,  the  particular  coal  of  any  location 
must  be  tested. 

OF  THE  COMPARATIVE  VALUE  OF  WOOD,  COAL,  AND  COKE. 

This  question  divides  itself  into  two  parts, 


EQUIPMENT.  325 

The  relative  cost  of  the  different  fuels, 
and  The  relative  power  to  produce  heat. 

319.  It  does  not  follow  that  because  coke  in  England, 
anthracite  in  Pennsylvania,  or  wood  in  New  England,  is  the 
most  economical  fuel,  that  either  of  the  above  will  be  so  in 
Ohio,  Indiana,  or  Illinois,  or  because  wood  is  the  cheapest 
in  some  parts  of  a  State,  that  it  is  so  throughout,  or  even 
that  one  fuel  should  be  applied  to  the  whole  length  of  a 
single  road. 

The  heat  used  to  evaporate  water  in  the  locomotive 
boiler  is  developed  by  combustion ;  combustion  is  produced 
by  chemically  combining  the  oxygen  of  the  air  with  the 
carbon  of  the  fuel ;  whence,  that  material  containing  in  a 
given  cost  the  largest  amount  of  carbon  will  produce  heat 
the  most  economically. 

From  the  table  on  page  320,  we  see  that,  by  bulk,  thirteen 
of  coke  are  equal  to  sixty  of  wood;  that  one  pound  of 
coke  evaporates  eight  and  one  half  pounds  of  water ;  that 
one  pound  of  wood  will  evaporate  two  and  one  half  pounds 
of  water.  Tables  of  specific  gravity  give  as  an  average 
weight  per  cubic  foot  of  hard  wood,  thirty  pounds.  A  cord 
of  wood,  by  very  careful  measurement,  contains  one  hun 
dred  cubic  feet  solid,  or  one  hundred  twenty-eight  feet  as 
piled,  taking  the  average  size  of  wood ;  whence  a  cord  will 
weigh  three  thousand  pounds.  And  we  have  as  the  relative 
evaporative  efficiency  of  a  cord  of  wood  and  a  ton  of  coke, 

2240X81  =  19040, 
3000X2^=:   7500. 

Now  if  the  cost  of  a  cord  of  wood  is  to  the  price  of 
a  ton  of  coke  as  7,500  to  19,040,  it  is  immaterial  which 
we  use. 

As  an  example  of  the  use  of  the  above  proportion,  when 

28 


326  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

the  absolute  cost  of  wood,  coal,  coke,  and  labor  are  known, 
take  the  following. 

If  wood,  cut  and  ready  for  burning,  costs  $3.00  per  cord, 
how  much  may  be  given  for  a  ton  of  coke  ? 

As  7,500  is  to  19,040,  so  is  300  to  762,  or  $7.62. 
From  the  same  proportion  we  form  the  following  table. 

Cost  per  cord  of  wood  Price  that  may  be  paid 

ready  for  burning.  per  ton  for  coke. 

(Cents.)  (Cents.) 

200  508 

225  571 

250  635 

275  698 

300  762 

325  825 

350  877 

375  952 

400  1016 

425  1079 

450  1143 

475  1206 

500  1270 

In  the  comparison  above,  the  maximum  evaporative 
power  of  wood  has  been  used,  2i  Ibs.,  and  the  ordinary 
power  of  coke,  8J  Ibs.  of  water  per  pound  of  fuel. 

320.  In  making  coke  in  large  quantities,  the  ovens 
should  be  at  the  mines,  as  we  thus  save  transporting  the 
extra  weight  of  coal  over  coke. 

The  cost  of  making  coke,  exclusive  of  the  cost  of  the  coal, 
is  approximately  as  follows  :  — 

10  ovens  capable  of  making  annually  5,000  tons  of  coke,      $5,000 

Sheds,  and  apparatus  to  correspond,  3,000 

In  all,  8,000 


EQUIPMENT.  327 


Annual  interest  at  6  per  cent., 
Annual  cost  of  attendance,  2  men, 
The  sum  of  which  is, 
And  the  cost  per  ton, 


or  in  round  numbers,  thirty  cents  per  ton ;  and  if  coal  is 
$1.50  per  ton,  adding  twenty-five  per  cent,  we  have  $1.87 
as  the  cost  of  coal  that  will  make  one  ton  of  coke,  to  which 
add  the  cost  of  making  per  ton,  thirty  cents,  and  we  have  as 
the  whole  cost  of  one  ton  of  coke  $2.17 ;  and  from  the  rule 
on  page  327  we  see  that  wood  must  not  cost  over  $0.85 
per  cord  to  be  as  economical  as  coke  at  $2.17 ;  of  course 
inferior  qualities  of  coal  will  give  less  good  coke  and  change 
the  comparison. 

COMBUSTION. 

321.  The  combustible  element  in  all  fuels  is  carbon ;  the 
heat  necessary  for  steam  producing,  is  obtained  by  combin 
ing  the  carbon  of  the  fuel  with  the  oxygen  of  the  air,  form 
ing  carbonic  acid  gas. 

Carbonic  acid  gas  consists  of 

Oxygen     16  )  Parts  by 
Carbon        6  )   weight. 

Atmospheric  air  consists  of 

Oxygen       8  )  Parts  by 
Nitrogen  28  }  weight. 

Whence,  for  the  combustion  of  one  pound  of  carbon,  we 
require 

Carbon         .         .         .         .         1.00 
Oxygen 2.66 


328  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

But  to  obtain  2.66  of  oxygen  from  the  atmospheric  air, 
we  also  use  nitrogen  in  the  proportion  of  28  nitrogen  to  8 
oxygen ;  whence,  for  converting  one  pound  of  carbon  to 
carbonic  acid,  we  require 

Oxygen  .  .  .  2.66 
Nitrogen  .  .  9.31 
Or  .  L.  11.97  Ibs.  of  atmospheric  air. 

From  careful  observations  on  the  gases  passing  through 
the  chimneys  of  well-constructed  boilers,  oxygen  is  found 
free,  varying  in  amount  from  one  quarter  to  one  half  of  the 
quantity  necessary  for  combustion;  this  is  owing  to  the 
mechanical  obstructions  to  the  perfect  conversion  of  the  air 
arising  from  leakage  through  the  fuel. 

More  than  the  above  11.97  Ibs.  of  air  should,  therefore,  be 
applied  to  the  fire  for  each  pound  of  carbon  consumed. 
Twenty-five  per  cent,  is  found  by  experience  to  be  a  suffi 
cient  surplus  allowance  to  convert  the  carbon. 

Whence,  to    11.97 
add  3.03 

and  we  have  15.00  Ibs.  of  atmospheric  air  per  Ib.  of  carbon. 

Air  weighs  .075  Ibs.  per  cubic  foot,  whence  .-fifc  or  200 
cubic  feet  of  air  are  necessary  for  the  proper  combustion  of 
one  Ib.  of  pure  carbon. 

Knowing  the  necessary  amount  of  air  for  one  Ib.  of  car 
bon,  and  also  the  percentage  of  carbon  in  the  different  kinds 
of  fuel,  it  becomes  a  simple  arithmetical  operation  to  fix  the 
bulk  of  air  required  for  any  species  of  coal,  coke,  or  wood. 
The  result  of  such  a  calculation  is  shown  in  the  seventh 
column  of  the  table  on  page  320. 

"  There  are  two  causes  why  all  the  heat  which  fuel  may 
furnish  is  not  obtained.  First,  that  the  inflammable  gases 


EQUIPMENT.  329 

evolved  by  the  heat  are  not  all  consumed  from  want  of  a 
sufficient  supply  of  oxygen,  the  air  drawn  through  the  fire 
being  only  sufficient  to  decompose  more  fuel  than  when  de 
composed  it  could  burn,  or  supply  with  oxygen.  The  thick 
smoke  that  escapes  from  a  chimney  when  fresh  fuel  is 
thrown  on  a  hot  fire,  is  unconsumed  gas;  decomposed  from 
the  fuel,  but  without  oxygen  enough  to  burn  —  although 
there  may  have  been  a  sufficient  supply  of  heat.  From  this 
cause  it  is,  perhaps,  that  flame  is  seen  coming  from  the  top 
of  a  steamboat  chimney  which  appears  to  be  continuous 
from  the  furnace ;  but  which,  in  fact,  is  ignited  by  contact 
with  the  air,  having  retained  sufficient  heat  for  that  pur 
pose. 

"  All  smoke-consuming  furnaces  are  simply  means  of 
admitting  fresh  air  to  the  unconsumed  gases  above  the  fire, 
which,  in  a  common  chimney,  will  effect  the  object,  as  so 
large  a  mass  of  smoke  retains  the  necessary  amount  of 
heat.  This  only  prevents  the  nuisance  of  smoke.  To  ren 
der  the  gases  thus  reheated  useful  in  evaporating  water, 
this  supply  of  oxygen  must  be  added  while  the  gases  are 
yet  in  the  flues."  This  might  seem  difficult.  Mr.  McCon- 
nell  (England)  divides  the  flues  of  his  locomotives  into  two 
parts,  connecting  the  front  ends  of  the  first  part  and  the 
back  ends  of  the  second  part  by  a  space  of  twelve  or  fifteen 
inches,  (called  by  him  a  l  combustion  chamber,')  into  which 
he  admits  any  required  amount  of  fresh  air.  (See  appendix 
E.) 

"  A  second  cause  why  the  full  value  of  the  fuel  produced  is 
not  obtained  is,  that  so  much  is  abstracted  from  the  gases 
in  passing  through  long  tubes,  that  there  is  not  enough  left 
to  continue  combustion,  although  the  inflammable  gas  is 
still  there.  That  a  tube  or  any  substance  in  the  way  of  the 
hot  gases  does  absorb  the  heat  enough  to  prevent  the  burn 
ing  of  the  gas,  is  proved  by  the  action  of  Davy's  Safety 

28* 


330  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Lamp ;  this  is  a  common  light  surrounded  by  a  wire  gauze, 
which  so  absorbs  the  heat  from  the  flame  as  to  extinguish 
the  latter  at  the  wire  ;  by  applying  fire  above  the  gauze,  the 
gas  is  again  kindled,  showing  plainly  that  want  of  heat 
above  had  quenched  the  flame."  See  Stockhardt's  Chem 
istry  ;  translation  by  C.  H.  Peirce,  M.  D.,  Cambridge,  Mass., 
1852,  page  105. 

We  require,  then,  in  every  boiler,  first,  to  have  a  sufficient 
supply  of  oxygen  to  decompose  the  fuel ;  next,  a  quantity 
above  the  fire  to  consume  the  produced  gases ;  third,  such 
an  arrangement  of  communicating  surface  that  so  much 
heat  shall  not  be  abstracted  from  the  gases  as  to  deaden 
their  combustion,  until  just  as  they  are  discharged,  at  which 
period  they  ought  to  be  consumed.  (See  appendix  E.) 


GENERATION  OF   STEAM. 

322.  The  means  of  producing  the  power  is  of  course  of 
the  first  importance. 

The  heat  generated  in  the  fire-box  is  conducted  through 
the  tubes  to  the  exhaust  chamber ;  during  which  passage  it 
is  imparted  to  the  metal,  and  from  thence  absorbed  by  the 
adjacent  water,  which  being  thereby  made  lighter,  rises  to 
the  surface  and  gives  place  to  a  new  supply.  The  duty  of 
the  furnace  is  to  generate,  and  of  the  tubes  to  communicate, 
heat 

The  power  of  a  plain  surface  to  generate  steam,  depends 
upon  its  position  and  on  the  ability  of  the  material  to 
transmit  heat  An  experiment  recorded  in  Clark's  Railway 
Machinery,  gave  the  following  results :  A  cubic  metallic  box 
submerged  in  water  and  heated  from  within,  generated 
steam  from  its  upper  surface  more  than  twice  as  fast  as 
from  the  sides  when  vertical,  while  the  bottom  yielded  none 


EQUIPMENT.  331 

at  all.  By  slightly  inclining  the  box  the  elevated  side  pro 
duced  steam  much  faster,  while  the  depressed  one  parted  so 
badly  with  it  as  to  cause  overheating  of  the  metal. 

Acting  upon  this  result,  most  builders  of  engines  of  the 
present  day  give  an  inclination  of  from  one  inch  to  one 
quarter  of  an  inch  per  foot  to  the  sides  of  the  inner  fire-box. 
That  the  heat  should  be  applied  in  the  most  effectual  man 
ner  to  the  water,  the  latter  should  circulate  freely  around  the 
hot  rnetal,  carrying  off  the  heat  as  soon  as  it  reaches  the 
surface.  As  the  heat  is  applied  to  the  inside  of  the  furnace 
and  tubes,  it  must,  therefore,  be  the  inside  dimensions  which 
determine  the  amount  of  heating  surface. 

NOTE.  —  If  we  multiply  the  interior  surface  of  a  tube  by  the  intensity  of  heat 
applied,  and  divide  the  product  by  the  exterior  surface,  we  shall  have  the  inten 
sity  at  the  outside.  "We  also  apply  more  heat  to  the  outside  of  a  tube,  which, 
passing  to  the  inner  surface,  augments  in  intensity  per  unit  of  area. 

The  area  of  the  inner  fire-box  is  not  all  available  for  heat 
ing,  but  requires  to  be  reduced  as  follows :  — 

For  the  fire-door. 
For  the  ferrule  area. 
For  the  top  stays. 
For  the  side  stay  bolts. 

The  area  is,  therefore. 

Sides,  twice  length  by  height,  less  stay  bolts.    . 
Back,  twice  height  by  breadth,  less  fire-door. 
Front,  twice  height  by  breadth,  less  ferrule  area. 
Top,  twice  length  by  breadth,  less  top  stays. 

TUBES. 

323.  The  tubes  or  flues,  varying  in  number  from  one 
hundred  to  three  hundred,  in  diameter  from  one  and  a  half 
to  three  inches,  and  in  length  from  eight  to  sixteen  feet,  fur- 


332  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

nish  the  real  communicating  surface.  The  amount  of  heat 
ing  surface  thus  obtained  for  any  length,  number,  and 
diameter,  is  given  in  table  10,  Chapter  XIV.,  Part  I.  The 
surface  of  a  single  tube  is  found  by  the  formula 

LdS.UlS 

144 ' 

Where  L  =  the  length, 

and  d=the  diameter,  both  in  inches. 

The  efficiency  of  circular  tubes  is  a  matter  not  yet  fully 
understood.  They  certainly  give  a  large  amount  of  sur 
face  in  a  small  boiler.  Pambour  considered  the  value  of 
tube  area  per  unit  of  surface,  in  terms  of  the  furnace  area, 
as  one  third  only ;  that  is,  three  square  feet  of  tube  surface 
as  equal  to  one  foot  of  furnace  area,  in  power  of  generating 
steam.  D.  K.  Clark  makes  no  distinction  between  the  two 
surfaces,  but  observes  "  there  is  reason  to  believe  that  in  the 
upper  semicircular  part  of  each  tube  the  efficiency  princi 
pally  resides.  The  winding  progressive  motion,  observable 
in  tubes  of  considerable  diameter,  confirms  this  conclusion, 
as  it  is  with  much  probability  due  to  the  cooling  of  the 
upper  portion  of  the  gases  of  combustion,  which,  as  they 
cool  also,  become  heavier  and  descend  laterally,  to  make 
room  for  the  hotter  smoke  next  the  bottom  of  the  flue ;  the 
general  result  of  which  is  the  spiral  motion  of  the  current 
in  its  progress  onwards."  Certainly  the  upper  half  of  the 
tube  would  part  much  easier  with  the  steam  than  the 
under  one,  even  supposing  the  applied  heat  to  be  the  same. 

At  page  340  of  "  Overman's  Mechanics,"  is  the  follow 
ing  :  "  The  application  of  heat  to  a  concave  surface  is  wrong 
in  principle.  The  heat  in  gases  is  conducted  to  other 
bodies,  and  among  themselves  by  convection  only.  This 
quality  of  gases  causes  the  convex  form  of  a  vessel  to  be 


EQUIPMENT.  333 

the  most  profitable  in  absorbing  the  heat  of  ascending 
gases,  because  the  motion  of  the  gas  causes  a  constant 
change  of  particles  on  the  convex  body.  On  a  concave  sur 
face  exposed  to  the  influence  of  moving  gases,  but  little 
effect  is  produced ;  because  the  particles  of  gas  in  the  con 
cavity  are  at  rest  A  plane  surface  is  for  the  same  reason 
an  imperfect  form  for  absorbing  heat ;  it  must  be  exposed 
at  an  angle  of  45°  to  obtain  the  best  effect  of  the  heating 
gases.  In  all  cases  if  we  wish  to  obtain  the  best  effect 
from  the  fuel,  we  should  expose  a  convex  surface  to  the 
current  of  hot  air.  The  direction  of  the  motion  of  the  hot 
gases  decides  the  position  of  the  metal  which  is  to  absorb 
the  heat ;  if  the  current  is  horizontal  the  pipes  must  be  ver 
tical.  Gases  do  not  convey  heat  by  radiation.  Tubes  and 
other  vessels  containing  water  must  be  so  placed  that  the 
hot  gases  play  around  the  outside. 

"  If  we  lead  a  current  of  hot  air  around  a  cylinder  we 
shall  observe  that  a  particle  of  air  plays  but  a  short  time 
upon  its  surface,  when  it  gives  way  to  another ;  the  parti 
cles  play  almost  around  the  cylinder,  and  a  concentration 
or  increase  of  density  behind  the  pipe  is  the  result.  The 
relative  position  of  pipes  in  the  range  is  not  indifferent,  and 
the  distance  of  one  from  the  other  must  be  related  to  their 
diameter." 

The  conducting  power  of  the  metal  composing  the  fire 
box  and  tubes,  is  one  condition  which  limits  the  rate  of 
evaporation,  when  the  heat  is  abundant  on  the  one  side  and 
circulation  free  on  the  other,  as  the  water  certainly  carries 
off  the  heat  as  fast  as  it  arives  at  the  outer  surface. 

All  the  heat  should  be  extracted  if  possible  from  the 
gases  before  they  enter  the  smoke  box.  We  should  so 
arrange  the  flues,  that  without  so  much  contracting  the  pas 
sage  for  the  exit  of  the  gases  as  to  need  too  strong  a  blast, 
yet  to  confine  the  gases  until  their  full  value  is  extracted. 


334  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Several  attempts  have  been  made  to  apply  the  ideas  of 
Clark  and  Overman,  but  as  yet  they  have  been  very  indirect 
and  have  met  with  only  moderate  success.  (See  Appen 
dix,  E.) 

EVAPORATION,    PRESSURE,    TEMPERATURE,    AND    DENSITY. 

324.  The  character  of  work  to  be  done  determines  the 
nature  of  the  steam  to  be  used. 

The  quantity  of  work  to  be  done  shows  the  amount  of 
steam  to  be  produced. 

The  amount  and  character  of  the  steam  required,  fixes 
the  dimensions  and  proportions  of  the  boiler. 

A  cubic  foot  of  water,  at  a  temperature  of  62°,  weighs 
62.321  Ibs. 

A  cubic  foot  of  steam,  generated  at  212°  Fahrenheit, 
under  the  atmospheric  pressure  (44.7  Ibs.  per  square  inch) 
weighs  .03666  Ibs. 

Whence  one  cubic  foot  of  water  boiled  at  212°,  makes 
1,700  cubic  feet  of  steam. 

The  total  heat  of  saturated  steam  (steam  produced  in 
contact  with  the  water),  consists  of  two  parts  at  all  temper 
atures  ;  the  latent  and  the  sensible.  The  sensible  heat  is 
that  shown  by  the  thermometer,  and  varies  with  the  pres 
sure.  The  latent  heat  absorbed  during  the  generation  of 
steam,  amounts  to  three  fourths  of  the  whole.  As  the  tem 
perature  at  which  the  steam  is  produced  increases,  the  bulk 
produced  from  a  given  unit  of  water  decreases,  but  the 
pressure  and  the  total  heat  increase.  (See  C.  R.  M.  p.  59, 
61,  Regnault's  experiments.) 

Table  8,  Chapter  XIV.,  Part  I.,  gives  the  properties  of 
saturated  steam,  produced  under  pressures  varying  from 
fifty  to  one  hundred  and  fifty  pounds  per  square  inch. 

The  steam  produced  over  water  is  called  saturated,  and 


EQUIPMENT.  335 

an  application  of  heat  to  an  isolated  volume  of  this  steam, 
raises  both  the  temperature  and  pressure,  the  volume  and 
density  remaining  the  same.  The  saturation  is  then  no 
more,  and  the  steam  is  surcharged.  If  the  heat  be  with 
drawn,  pressure  and  density  fall,  and  a  precipitation  of 
water  takes  place.  The  priming  of  steam  in  a  cylinder  is 
an  illustration  of  this.  D.  K.  Clark,  in  Railway  Mechanics, 
urges  the  necessity  of  thoroughly  drying  the  steam  before 
applying  it  to  the  pistons ;  in  this  manner,  he  says,  ten  per 
cent,  may  be  gained  at  two  velocities,  and  in  some  cases 
forty  per  cent,  at  high  speeds. 

MOTION    OF   STEAM   IN   PIPES. 

325.  Steam  may  flow  from  any  vessel  into  a  vacuum, 
into  the  open  air,  or  into  steam  of  a  less  density.  The 
velocity  of  efflux  of  steam  is  the  same  as  that  of  a  stream 
of  water  flowing  under  a  pressure  equal  to  that  of  the 
steam.  Steam  flowing  into  the  atmosphere  of  course  has 
14.7  Ibs.  per  inch  resistance  to  meet,  which  is  equivalent  to 
a  reduction  of  14.7  Ibs.  of  its  pressure.  The  following 
numbers  show  the  velocity  of  efflux  of  steam  into  the  open 
air  under  different  pressures. 

Pressure.  Velocity,  in  feet,  per  second. 

50  1791 

60  1838 

70  1877 

80  1919 

90  1936 

100  1957 

110  1972 

120  1990 

130  2004 


336  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


LOSS    OF   PRESSURE    CAUSED    BY   THE   MOTION    OF    STEAM. 

326.  The  loss  of  power  suffered  by  the  steam  during  its 
motion  from  the  boiler  to  the  cylinder  is  caused  by  con 
densation  in  passing  through  cold  pipes,  and  by  friction  and 
sharp  bends.  The  total  fall  that  may  be  caused  by  a  com 
bination  of  circumstances  is  from  ten  to  fifteen  per  cent,  at 
low  velocities,  and  from  fifty  to  sixty  per  cent,  at  high 
speeds.  The  fall  of  pressure  decreases  as  the  square  of  the 
velocity  of  motion,  that  is,  the  fall  at  a  velocity  of  1,600 
feet  per  second  is  four  times  as  great  as  the  fall  at  a  velocity 
of  eight  hundred  feet.  By  well  protecting  the  steam  pipes 
and  cylinders,  and  by  drying,  it  may  be  worked  at  nearly 
its  initial  pressure. 


APPLICATION   OF  STEAM. 

327.  The  steam  being  generated  in  the  boiler,  and  con 
veyed  to  the  cylinders,  is  admitted  alternately  to  the  oppo 
site  sides  of  the  piston,  by  which  its  reciprocations  are 
produced.  The  first  valve  applied  to  regulating  the  ad 
mission  of  steam  to  the  cylinder  was  so  arranged  that  the 
steam  was  admitted  during  the  whole  stroke ;  at  the  end 
of  which,  ingress  stopped  and  egress  commenced  at  the  first 
end,  and  ingress  commenced  at  the  second  end  simul 
taneously  ;  this  caused  an  unnecessary  resistance  to  the 
return  movement,  by  preventing  the  quick  escape  of  the 
first  cylinder-full,  which  had  to  be  pushed  out,  instead  of 
flowing  out.  The  continuance  of  the  full  pressure  upon  the 
piston  also,  until  the  end  of  the  stroke,  caused  a  dangerous 
momentum  to  be  given  to  the  reciprocating  machinery. 

These  evils  are  obviated  by  causing  the  exhaust  passage 
to  open,  and  the  entering  part  to  close  a  little  before  the  end 


EQUIPMENT.  337 

of  the  stroke.  This  is  effected  by  moving  the  valve  bodily 
forward. 

Now  it  is  well  ascertained,  that  with  very  free  steam 
entrances,  if  we  allow  the  cylinder  to  be  only  partially  filled, 
and  then  cause  the  steam  to  expand  itself,  more  work  is 
accomplished  with  a  given  bulk  than  when  the  cylinder  is 
completely  filled.  That  the  steam  may  have  time  thus  to 
expand  itself,  the  return  of  the  piston  must  not  take  place 
until  after  the  suppression  (the  stopping  of  admission). 

328.  There  are  four  positions  of  the  valve  during  each 
half  stroke,  and  three  distinct  actions  of  steam  in  the  same 
period,  which  are  as  follows:  — 

Position  of  valve.  Action  of  steam. 

Admission  (A). 

Entrance. 
Suppression.  • 

Expansion. 
Release. 

Compression. 
Admission  (B). 

The  longer  the  time  between  suppression  and  release,  of 
course  the  more  complete  will  be  the  expansion.  The  entire 
force  of  the  steam  should  not  (even  if  possible)  be  extracted, 
as  a  certain  force  is  necessary  to  produce  a  blast. 

The  time  of  expansion  is  regulated  by  the  proportions  of 
the  valve  cover ;  which  may  be  so  adjusted  as  to  fix  sup 
pression  or  release  at  any  desired  part  of  the  stroke. 

By  the  above  means  any  rate  of  expansion  may  be  es 
tablished,  but  when  once  fixed  will  remain  the  same,  the 
valve  being  invariably  connected  with  the  eccentric,  and 
thus  partaking  of  its  motion. 

329.  The  great  step  which  has  been  taken  in  locomotive 
construction  since  1840  is  the  invention  of  the  "  link  mo- 

29 


338  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

tion,"  by  Williams,  which,  perfected  by  Howe,  admits  of 
varying  the  travel  of  the  valve,  and  thus  using  the  steam 
under  any  desired  rate  of  expansion.  By  this  arrangement, 
the  power  of  regulating  the  force  applied  to  the  piston, 
according  to  the  work  to  be  done,  is  placed  in  the  engineer's 
hands,  to  be  used  at  any  time  under  whatever  conditions 
the  engine  may  be  working. 

By  this  arrangement,  two  eccentrics  to  each  cylinder  are 
required,  (and  in  some  dispositions  of  the  link,  only  one). 
Fig.  150  shows  the  general  plan  of  varying  the  expansion. 
A  fixed  relation  evidently  exists  between  the  points  A  and 
B,  two  distinct  motions  are  communicated  by  the  eccentrics 
C  and  D  through  the  rods  E  and  F,  to  the  two  ends  G  H, 
of  the  curved  link  L ;  the  eccentrics  are  so  adjusted  upon 
the  driving  axle  as  to  cause  the  two  ends  of  the  link  to 
move  in  opposite  directions,  whence  at  some  point  midway 
there  is  no  motion ;  the  link  is  movable  (vertically)  upon 
the  suspended  point  L,  so  that  by  bringing  L  to  one  end  or 
the  other,  the  motion  given  to  the  rod  m  partakes  of  the 
motion  of  that  eccentric  which  is  nearest  to  it.  Thus  the 
movement  of  the  valve  may  be  checked,  or  even  reversed  in 
a  second,  while  the  engine  is  in  motion,  and  that  without 
sudden  shocks. 

The  link  is  moved  by  the  levers  n  n'  n"  terminating  in  the 
bar  O,  placed  at  the  foot  board  of  the  engine  in  reach  of 
the  engineer.  Applied  to  this  is  an  iron  sector  7i/i'A",  made 
fast  to  the  frame  of  the  engine.  Now  when  the  point  L  is 
in  such  a  part  of  the  link  as  to  place  the  valve  in  a  position 
admitting  steam  for  any  fraction  of  the  stroke,  let  the  point 
at  which  the  bar  O  stands  upon  the  sector  be  marked  for 
that  admission ;  and  so  also  for  any  number  of  different 
degrees  of  expansion.  It  is  plain  that  the  engineer  may 
thus,  by  fixing  the  lever  O,  use  any  percentage  of  admission 
that  is  required ;  and  may  always  know  just  what  duty  the 


EQUIPMENT.  339 

engine  is  doing.    Five  minutes'  examination  of  the  reversing 
gear  upon  an  engine  will  render  the  operation  plain. 

330.  If  we  cut  the  steam  off  at  half  stroke  and* then 
allow  it  to  expand,  of  course  the  mean  pressure  during  the 
whole  stroke  is  less  than  that  at  entering.     The  effective 
mean   pressure  obtained   by   any  degree   of  expansion   is 
shown  by  the  following  formula,  deduced  from  a  mean  of 
forty-nine  experiments  with  the  Great  Britain  locomotive, 
(Great    Western    Railroad,    England,)    having    cylinders 
18  X  24.' 

13.5  (  y/"o~ —  28  j  =  mean  pressure 

where  a  is  the  percentage  of  admission. 
From  this  formula,  table  11  is  made. 

331.  Mr.  Clark  deduces  as  general  results,  from  a  very 
extensive  and  carefully  conducted  system  of  experiments, 
the  following. 

That  the  maximum  useful  admission  is  seventy-five  per 
cent. 

The  minimum  useful  admission  ten  per  cent. 

The  greatest  possible  gain  by  working  expansively  is  one 
hundred  per  cent,  which  is  effected  by  an  admission  of  ten 
per  cent. 

The  best  admission  for  engines  having  ports  ^  of  the 
area  of  the  piston,  and  blast  area  from  TV  to  TV  of  piston,  at 
high  speeds  (from  thirty  to  sixty  miles  per  hour)  and  with 
considerable  loads,  is  from  sixty  to  sixty-six  per  cent.  With 
a  wider  port  and  blast  area,  the  best  admission  is  seventy- 
five  per  cent. 

The  resistance  due  to  the  back  pressure  of  the  blast, 
varies  as  the  speed  squared,  and  inversely  as  the  square  of 
the  area  of  blast  orifice. 

332.  From  the  experiments  made  by  Daniel  Gooch,  with 
the  engine  "  Great  Britain,"  the  following  results  appear. 


340  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

The  loss  of  fuel  at  seventy-five  per  cent,  admission,  the 
blast  orifice  being  from  ^  to  ^  of  piston  at  sixty  miles  per 
hour,,  is  from  %  to  TV ;  at  thirty  or  forty  per  cent,  admission, 
the  loss  is  from  J  to  51G ;  and  at  thirty  miles  per  hour,  (sev 
enty-five  per  cent,  admission,)  from  rV  to  ^. 

The  resistance  from  steam  compressed  in  the  cylinder, 
increases  with  the  speed,  and  also  with  the  degree  of  ex 
pansion  ;  it  varies  from  eight  per  cent,  in  full  gear,  (seventy- 
five  per  cent.,)  to  twenty-eight  per  cent,  at  an  admission  of 
forty  per  cent. 

At  the  highest  velocities,  the  whole  resistance  from  back 
pressure  is  nearly  the  same  for  all  expansions;  for  com 
pression  increases  as  blast  pressure  decreases. 

The  above  deductions  hold  good  for  speeds  under  forty 
miles  per  hour,  with  steam  ports  at  least  ^  and  blast  orifice 
from  TV  to  ^g  of  the  piston  area. 


OF  BOILER  PROPORTIONS. 

333.  The  dimensions  of  American  locomotives  seem  to 
depend  more  upon  the  shop  whence  they  come,  than  upon 
any  special  duty  required  of  them.     It  is  not  surprising  that 
the  utmost  economy  is    seldom   attained  when  a  railroad 
president  orders   a  lot  of  locomotives,  from  the  cheapest 
builder,  to  suit  his  own  ideas  of  an  engine  ;  or  when  engines 
are  ordered  by  a  superintendent  of  machinery  who  does  not 
know  the  difference  between  a  sixty  foot  grade  and  a  level. 
It  is  the  affair  of  the  company's  agent  and  not  of  the  ma 
chinist  to  know  just  what  a  railroad  needs.     It  is  a  com 
mon,  and  most  absurd  practice,  for  a  man  who  is  completely 
ignorant  of  machinery  to  order  five  or  ten  engines,  without 
the  least  regard  to  the  character  of  the  road  or  of  the  traffic. 

334.  The  particular  characteristics  of  each  class  of  en- 


EQUIPMENT.  341 

gines  is  entirely  a  matter  of  figures.  There  is  no  reason 
why  a  general  table  should  not  be  formed  embracing  all 
divisions,  orders,  and  classes  of  locomotives,  in  which  the 
requirements  and  general  dimensions  corresponding  thereto 
should  be  laid  down  for  machine  shop  reference.  Such  a 
table  would  at  once  establish  a  mutual  understanding  be 
tween  railroad  companies  and  builders.  Such  a  general 
classification  is  shown  hereaftar.  The  dimensions  of  en 
gines  are  not  given,  as  it  was  thought  best  to  let  each 
person  fill  it  up  according  to  his  own  ideas.  By  so  doing 
some  valuable  general  properties  may  be  arrived  at. 

335.  Thus  far  experience  has  been  the  only  guide  to 
proportion  (in  America  at  least).  Practice,  in  many  things, 
is  the  only  correct  path  to  the  right  results,  but  locomotives 
are  too  expensive  for  philosophical  apparatus ;  correct  ex 
periments  upon  imperfect  machines  will  lead  to  the  means 
of  avoiding  errors.  The  following  is  the  modus  operandi 
of  D.  K.  Clark  in  his  "  Railway  Machinery." 

A  number  of  engines  of  different  proportions  are  chosen, 
and  observations  made  upon  the  amounts  of  fuel  and  water 
consumed  upon  the  work  done,  and  under  what  conditions. 
These  results  are  so  tabulated  as  to  show  the  effect  in  dif 
ference  of  construction  upon  the  performance  of  the  engine, 
whence  the  proportioning  of  parts  becomes  a  simple  arith 
metical  operation.  The  reduction  of  experiments  to  tables, 
and  the  deduction  from  tables  of  formulae,  is  a  simple 
operation  compared  with  the  skill  and  care  required  in 
observing  the  operation  of  a  machine,  subject  to  so  many 
disturbances  as  a  locomotive  engine  in  rapid  motion.  None 
have  had  a  better  opportunity  of  observing,  have  conducted 
experiments  with  more  care,  or  have  obtained  results  which 
show  fewer  discrepancies  than  the  English  engineers  Clark 
and  Gooch,  and  the  French  and  German  observers  Le  Chat- 

lier  and  Nollan. 

29* 


342  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

336.  Three  essential  parts  of  the  locomotive  are  the  grate 
area,  heating  surface,  and  cylinders.     No  two  writers  upon 
this  subject  arrive  at  the  same  dimensions  to  perform  the 
same  work.     They  not  only  differ,  but  differ  widely.     They 
cannot  all  be  right;    all   but   one,  or  all  must   be  wrong. 
American  builders  have  fixed  the  dimensions  of  their  en 
gines  by  observing  the  performance  of  constructed  machines, 
not  by  rules  deduced  from  any  systematic  experiments,  but 
upon  a  system  of  remedying  visible  errors.     If  a  chimney 
diameter  of  ten  inches  is  found  too  small  and  twenty  too 
large,  fifteen  has  been  assumed  as  about  right. 

337.  As  an  example  of  the  difference  in  the  results  ob 
tained  by  different  authors,  take  the  following  :  — 

An  engine  to  do  the  same  work  must  have,  according  to 


Zerah  Colburn.l 

Norris.2 

D.  K.  Clark.s 

D.  K.  Clark.* 

18  X  22 
5 

18X22 
5 

18X22 
5 

18  X  22 

5 

Cylinders. 
Wheels. 

13.00 

13.86 

14.00 

19.60 

Grate  area. 

1114 

250 
4 
59 
100 

812 
324 
23 
73 
72 

1327 
134 

28 

1327 
134 

28 

Heating  surface. 
Area  of  chimney. 
Area  of  blast. 
Steam  room. 

"Wntpr  rnnm 

i 

From  these  figures,  the  work  done  being  the  same,  Mr. 
Clark  gives  forty  per  cent,  more  grate  area  than  either  Col- 
burn  or  Norris,  an  easier  blast,  and  greater  heating  surface. 
Norris  makes  the  steam  and  water  room  equal,  while  Col- 
burn  makes  the  latter  almost  double  the  former.  It  is  to 


1  Colburn  on  the  Locomotive  Engine. 

2  Norris's  Handbook  for  Locomotive  Engineers  and  Machinists. 
8  D.  K.  Clark's  Kailway  Machinery,  calculated  for  coke. 

*  D.  K.  Clark's  Railway  Machinery,  calculated  for  wood. 


EQUIPMENT.  343 

be  observed  that  Colburn  gives  only  rules  adopted  by  differ 
ent  builders,  not  vouching  for  their  correctness,  while  Norris 
lays  down  his  rules  as  fixed  and  right.  The  engines  used 
by  the  English  experimenters  in  their  observations,  vary  in 
dimension  between  the  following  wide  limits,  whence  the 
universal  application  of  their  results. 

Grate  area     .         .         .  .    9  to       24  square  feet. 
Fire  surface      V'      .        '.'      50  to     100       «         " 

Tube  surface       '  '?**  •  V  400  to  1,000       "         " 

Whole  surface   .       '.         .  450  to  1,100       «         « 
Blast  orifice   .         .         .  10  to       20  sq.  inches,  area. 

Speed  of  engine         .         .       12  to       20  miles  per  hour. 

338.  The  result  of  some  sixty  experiments  upon  forty- 
five  different  engines  (detailed  in  Clark's  Railway  Machinery, 
page  156),  gives  the  following  formula,  expressing  the  rela 
tions  which  ought  to  exist  between  grate  area,  heating  sur 
face,  and  consumption  of  water ;  that  evaporation  may  be 
carried  on  in  the  most  economical  manner. 

S=\JacX  2 1.2  =  surface. 

Where  S  is  the  heating  surface  in  square  feet. 
a  is  the  grate  area  in  square  feet. 
c  is  the  hourly  consumption  of  water  in  cubic  feet. 

From  which  we  deduce  the  value  of  a  or  c  thus, 

/  s  V 

a~  \2L27  =gratearea; 
c 

{  S  V 

and  c=.  (  ^j-x  )  =  hourly  water  consumption. 

a 

The  maximum  evaporation  which  should  be  carried  on 
per  square  foot  of  grate  is  found,  by  Mr.  Clark,  to  be  sixteen 


344  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

cubic  feet  per  hour.  Thus,  if  we  wish  to  evaporate  160 
cubic  feet  of  water  per  hour,  we  must  have  a  grate  area  of 
at  least  \6/  or  ten  square  feet. 

339.  The  above  formula  for  the  grate  area  gives  the 
dimension  for  a  coke-burning  furnace.  Locomotives  burn 
ing  wood  or  coal  require  a  modification  of  the  above,  as 
follows  :  — 

To  produce  a  given  amount  of  heat,  a  certain  amount  of 
carbon  must  be  burnt.  As  wood  contains  much  less  carbon 
than  coke,  a  correspondingly  larger  bulk  must  be  burnt,  and 
a  larger  grate  is  necessary  ;  not,  however,  larger  in  propor 
tion  to  the  larger  bulk  of  fuel,  as  we  may  have  a  deeper 
wood  than  coke  fire.  The  relative  depth  of  fire  being  as 
the  stowage  bulk,  and  the  actual  depth  of  a  coke  fire  being 
1.9  feet,  that  of  a  wood  fire  will  be  2.5  feet. 

Now  let  A  be  the  number  of  Ibs.  of  coke  per  foot  of  water 
evaporated. 

B  the  number  of  Ibs.  of  coal  per  foot  of  water  evapo 
rated. 

C  the  number  of  Ibs.  of  wood  per  foot  of  water  evapo 
rated. 

Call  d  the  depth  at  which  it  is  the  most  economical  to 
burn  coke  ;  d'  the  same  depth  /or  coal,  and  the  depth  for 
wood  d".  Then  will  the  area  of  a  coke  grate  be 


Of  a  coal  grate 

B 

d'' 

And  of  a  wood  grate 

Q 

d"' 


EQUIPMENT.  345 

To  be  able  to  fix  the  proper  grate  area  for  any  fuel,  we 
must  know  its  evaporative  power,  and  a  depth  of  a  layer 
in  the  furnace.  Knowing  the  absolute  value  for  coke,  it  re 
mains  only  to  obtain  the  relative  value  for  any  other.  Thus 
far  we  have  disregarded  the  difference  in  time  of  burning 
wood  and  coke.  To  produce  a  given  amount  of  heat,  we 
burn  a  certain  chemical  value  of  fuel;  a  much  larger 
bulk  of  wood  than  of  coke  is  needed.  If  we  burn  wood 
and  coke  at  the  same  depth  and  in  the  same  time,  the 
grate  areas  would  be  proportional  to  the  bulks  of  fuel  to 
produce  the  same  heat ;  but,  first,  we  burn  fuel  in  a  depth 
proportioned  to  the  economic  stowage  bulk,  or  as  2.5  to  1.9, 
which  decreases  the  wood  area ;  and,  second,  a  layer  of  coke 
1.9  feet  deep  burns  in  one  hour,  while  a  layer  of  wood  2i 
feet  deep  burns  in  fifteen  minutes ;  whence  60  m.  divided  by 
15m.  =  4  layers  of  2J  feet  deep  each,  or  in  all  ten  feet, 
which  into  the  bulk  (equal  to  a  mass  of  coke  1  foot  square 
X  1.9  high)  or  1  foot  square  by  14  high,  gives  14-^10  — 
1.4 :  or,  finally,  the  area  of  the  wood  grate  should  be  1.4 
times  that  of  a  grate  to  burn  coke. 

OP   THE    SIZE    AND*  USE    OP    THE    SMOKE    BOX. 

340.  The  smoke  box  is  the  general  termination  of  the 
flues,  and  the  place  where  the  vacuum  is  produced,  which 
causes  the  draft.  The  size  of  the  boiler  being  the  same, 
the  vacuum  varies  directly  as  the  blast  pressure.  The 
power  of  the  blast  is  of  course  affected  by  the  capacity  of 
the  smoke  box.  Mr.  Clark  fixes  the  capacity  of  the  exhaust 
chamber  at  three  cubic  feet  per  square  foot  of  grate.  The 
Vacuum  in  the  furnace  varies  from  one  to  two  thirds  of  that 
in  the  smoke  box.  The  less  the  resistance  to  the  hot  gases 
experienced  in  the  flues,  the  less  may  be  the  vacuum 
Upon  the  vacuum  depends  the  amount  of  air  drawn 


346  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

through  the  grate ;  upon  the  bulk  of  air  drawn  through 
the  grate  depends  the  combustion ;  upon  the  combustion 
the  evaporation.  Whence  the  evaporation  cet.  par.  depends 
the  vacuum  in  the  smoke  box. 

The  velocity  of  any  fluid  depends  upon  the  power  ap 
plied  to  it,  (being  as  the  square  root,)  the  pressure  applied 
to  the  gases  in  the  furnace  of  a  locomotive  is  the  vacuum 
in  the  smoke  box ;  thus  the  combustion  or  rate  of  evapora 
tion  is  as  the  square  root  of  this  vacuum.  To  double  the 
evaporation  it  is  necessary  to  quadruple  the  vacuum. 

BLAST  PIPE. 

341.  The  blast  pipe  conducts  the  waste  steam  from  the 
cylinder,  which  drives  the  air  from  the  chimney  and  pro 
duces  the  vacuum  in  the  smoke  box ;  its  form  should  per 
mit  the  freest  escape  of  the  steam  from  the  cylinder.     The 
blast  pipe  area  should   nowhere  be  smaller  than  the  exit 
part,  except  at  the  construction  at  the  top.      "  Too  much 
care,"  says  Mr.  Clark,  "  cannot  be  taken  to  adjust  the  blast 
pipe  concentrically  with  the  chimney ;   one  half  inch  has 
been   known  to  spoil  the  draft  of  a   locomotive."     "  The 
area  of  orifice  is  the  most  critical  and  most  important  item 
in  the  composition  of  the  locomotive." 

For  the  form,  dimensions,  and  influence  of  this  important 
member,  the  reader  is  referred  to  Clark's  Railway  Ma 
chinery. 

As  the  grate  area  increases,  the  blast  may  decrease. 
The  greater  the  flue  area  the  easier  may  be  the  blast ;  de 
crease  of  smoke  box  capacity  and  of  chimney  diameter, 
both  allow  a  milder  blast. 

342.  The  following  proportions  are  collected   from   the 
work  of  Mr.  Clark.     The  order  in  which  the  different  parts 
of  the  engine  stand  in  importance  with  relation  to  the  blast, 


EQUIPMENT.  347 

is  shown  in  column  1.  The  figures  show  the  ratios  (the 
best)  which  may  be  had  under  the  most  favorable  circum 
stances. 

Grate  area    .  ?  *>    .;»  >;     .     7  .  •      .         .';..•'       1 

Ferrule  area  (area  of  section  of  tubes  at  back  flue  sheet)  .  £ 
Tube,  sectional  area  #-,.  .  -!  t. :  .  -.  *»-  -  ,  .  .  . •  ,.f  ^ 
Capacity  of  smoke  box,  cubic  feet  .  ,,<.,-.  >.,-.  .  .3 
Chimney,  height  four  diameters,  area  of  section  .  .  ^ 
Blast  orifice  .  *  .  ,  .  .  .  .  .  •  75 

The  vacuum  in  the  smoke  box  is  somewhat  regulated  by 
a  damper  placed  in  front  of  the  ash  pan,  by  a  valve  in  the 
chimney,  or  by  a  Venetian  blind  covering  the  front  ends  of 
the  tubes. 

TUBE    SECTION    AND    LENGTH. 

343.  The  section  of  the  tubes  (crosswise)  is  the  space 
through  which  the  hot  gases  pass  off.  By  increasing  the 
length  or  decreasing  the  diameter,  we  of  course  require  a 
stronger  blast. 

That  the  steam  may  escape  as  soon  as  generated,  there 
must  be  a  certain  clearance  between  the  tubes,  which  Mr. 
Clark  fixes  as  follows  :  — 

Divide  the  number  of  tubes  by  thirty  and  the  result  is 
the  clearance  in  eighths  of  an  inch ;  or  algebraically 

SN\ 

C=  ( — )  =  clearance  in  inches ; 

"8         « 

I 

Or  otherwise 

N 
C=  srs  ==  clearance  in  inches. 


348  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


PROPORTIONS    OP    CYLINDERS    AND    WHEELS. 

344.  The  above   proportions   depend  entirely  upon  the 
nature  and  amount  of  work  to  be  done,  and  upon  the  char 
acter  of  the  road.     Small  wheels  and  long  stroke  are  to  be 
applied  to  heavy  trains  and  steep  grades.     Short  stroke  and 
large  wheels  to  fast  trains  and  level  roads. 

There  are  some  advantages  in  a  long  cylinder,  even  with 
a  constant  ratio  between  the  stroke  and  wheel  diameter. 
The  steam  has  more  time  to  expand ;  the  action  of  the  ma 
chinery  is  slower,  and  the  erratic  movements  of  the  engine 
caused  by  the  movement  of  the  reciprocating  machinery 
are  lessened,  at  the  same  time  the  centre  of  gravity  is 
raised  and  oscillation  increased. 

OF    THE    CARRIAGE. 

345.  The  arrangement  of  the  wheels,  axles,  springs,  and 
draw-link,  and  the  distribution  of  the  weight  of  the  engine 
upon  its  several  bearings  so  as  to  provide  the  necessary  ad 
hesion,  and  to  run  steadily  upon  the  rails,  is  a  matter  well 
worthy  of  more  attention  than  is  commonly  given  to  it. 

The  frame  is  the  base  of  the  engine,  to  which  every  thing 
should  be  attached.  The  cylinders  and  the  wheel  both 
being  attached  to  it,  it  of  course  becomes  the  counterpart 
to  the  piston  and  connecting  rod ;  the  former  holding  the 
cylinder  and  wheel  together,  while  the  latter  pushes  them 
apart.  The  frame  should  form  .a  rigid  connection  between 
the  piston  and  the  wheel ;  and  its  strength  must  be  able  to 
resist  the  whole  power  of  the  engine,  applied  alternately  as 
compression  and  as  extension. 

The  wheels  of  a  locomotive  answer  three  several  pur 
poses,  and  are  classed  as  follows  :  — 


EQUIPMENT.  349 

Leading  wheels. 

Driving  wheels.  •* 

Trailing  wheels. 

The  duty  of  the  driving  wheels  is  to  transfer  the  power 
of  the  engine  to  the  rails,  by  which  the  motion  is  produced. 
That  of  the  leading  wheels,  to  guide  the  engine ;  and  that 
of  the  trailing  wheels,  to  support  the  after  end  of  the  en 
gine. 

The  weight  upon  the  driving  wheels  must  be  enough  for 
sufficient  adhesion.  That  upon  the  leading  wheels,  suffi 
cient  to  guide  the  engine  upon  curves,  (decreasing  as  their 
distance  from  the  centre  of  gravity  becomes  greater,  and 
increasing  with  the  speed.) 

The  centre  of  gravity  of  an  engine  is  generally  at  a  dis 
tance  of  from  one  quarter  to  one  sixth  of  the  length  of  the 
barrel  from  the  furnace  horizontally  and  forwards,  and  in 
the  lower  part  of  the  barrel,  vertically. 

The  weight  upon  any  one  pair  of  wheels  is  as  their  dis 
tance  from  the  centre  of  gravity  ;  by  changing  their  position 
we  change  the  applied  weight. 

The  flange  base1  must  increase  as  the  engine  becomes 
heavier,  when  applied  to  fast  trains,  as  more  leverage  is 
necessary  to  keep  it  on  the  rails.  Heavy  freight  engines 
with  four  or  five  pairs  of  wheels,  and  no  truck,  wear  the 
rails  and  strain  themselves  very  much.  We  should  make 
the  wheels  of  such  very  small  and  near  together,  in  order 
to  contract  the  flange  base. 


1  Wheel  base,  —  Horizontal  length  between  centres  of  extreme  wheels.    Flange 
base,  —  Horizontal  length  between  centres  of  extreme  fixed  flanged  wheels. 

30 


350  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


DISTRIBUTION    OF    WEIGHT. 

346.  Suppose  the  whole  load  upon  the  wheels  is  60,000 
Ibs.  If  the  centre  of  gravity  is  half-way  between  the 
wheels  (there  being  two  pairs),  each  will  support  30,000  Ibs. 
If  the  centre  of  gravity  is  twice  as  near  to  one  axle  as  to 
the  other,  the  furthest  one  will  support  20,000  Ibs.,  and  the 
nearest  one  60,000  —  20,000,  or  40,000  Ibs. 

Suppose  the  engine  has  six  points  of  support,  or  three 
points  in  the  side  elevation,  (the  ordinary  four  driving 
wheels  and  a  truck  engine).  Let  the  centre  of  gravity  be 
one  foot  behind  the  middle  axle  and  the  distances  between 
the  wheel  centres  eight  feet. 

The  weight  upon  the  middle  axle  being  H,  that  upon  the 
hind  axle  is  ^  ,  because  that  axle  is  seven  times  more  dis 
tant  from  the  centre  of  gravity  than  the  middle  one,  and  for 
the  same  reason  the  weight  upon  the  front  axle  is  |f  . 

Now  H+      +      ^  60'00°  lbs' 


Whence  J7=  47,976  lbs. 

TJ 

Also,  -=  =  6,853  lbs. 


And       =  5,331  lbs. 
y 

And  the  same  laws  (see  article  Lever,  in  any  work  on 
Mechanics)  apply  to  any  arrangement  of  wheels  and  to  any 
position  of  centre  of  gravity. 

Springs  are  employed  to  absorb  the  shocks  received  by 
the  wheels  from  irregularities  in  the  surface  of  the  rails. 
They  must  be  equally  stiff  on  both  sides  of  the  engine,  or 
lateral  rocking  will  be  generated. 


EQUIPMENT. 


351 


Fig.  151. 


When,  as  is  generally  the  case,  the  springs  are  connected 
by  compensating  levers,  their  stiffness  being  as  the  load 
upon  them,  the  arms  of  the  connecting  lever  must  be 
inversely  proportional  to  the  applied  weights.  The  shock 
received  by  one  wheel  is  by  the  lever  communicated  to  the 
whole  four,  (or  even  more  when  there  are  such).  The  truck 
springs  of  some  builders  are  also  connected  by  an  equaliz 
ing  lever. 

According  to  Mr.  Clark,  not  more  than  twelve  tons  should 
ever  be  placed  upon  one  axle ;  whence  engines  requiring  a 
tractive  power  of  twelve  tons  and  less  may  be  of  the  form 
shown  in  fig.  151.  Be 
tween  twelve  and  twenty- 
four  tons,  of  the  form  fig. 
152  ;  and  over  twenty- 
four  of  the  forms  figs.  153, 
154,  and  155. 

The  weight  upon  the 
leading  wheels  of  fast 
passenger  engines  should 
be  as  much  as  one  fifth  of 
the  whole  weight.  Upon 
freight  engines  it  need  not 
be  more  than  one  sixth. 

The  line  of  traction  of 
a  locomotive  ought  to  be  as 
near  as  possible  at  the  same 
vertical  height  as  the  driving 
wheel  centres.     If  much   be 
low  this  the  load  will  tend  to 
lift  the   engine   off  from   the 
leading     wheels,     upon     the 
drivers   as   a   fulcrum,  thus  increasing  the   adhesion   and 
lessening  the  leading  power. 


352 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


If  the  traction  bar  (draw 
link)  is  above  the  wheel 
centres,  it  will  tend  to  lift 
the  rear  of  the  engine  from 
the  rails. 

The  general  form  of 
engines  used  in  America 
are  shown  in  figs.  151, 152, 
153, 154,  and  155. 

Fig.  151  is  the  express 
passenger  locomotive. 

Fig.  152  is  the  ordinary 
passenger,  mail,  and  mixed 
engine. 

Fig.  153  is  the  heavy  freight  engine. 
We  have,  also,  engines  with  three,  four,  and  five  pairs  of 
small  wheels  without  a  truck,  for  heavy  grades  and  large 
amounts  of  work. 


OF   ERRATIC    MOVEMENTS. 

347.  The  erratic  movements  of  a  locomotive  in  motion 
are  due  to  three  separate  causes. 

To  the  motion  of  the  machinery. 

To  the  arrangement  of  the  frame  and  wheels. 

To  the  state  of  the  surface  of  the  rails. 

Those  caused  by  the  motion  of  the  machinery  are  as  fol 
lows  :  Longitudinal  fore  and  aft  movement :,  generated  by  the 
reciprocations  of  the  piston  rod,  cross  head,  connecting  rod, 
and  crank ;  and  depending  in  amount  upon  the  weights  of 
the  moving  parts,  steam  pressure,  and  velocity  of  motion. 
Pitching  of  the  engine,  arising  from  the  oblique  action  of  the 
cross  heads  upon  the  guides,  which  tends  to  b'ft  the  front 


EQUIPMENT.  353 

end  of  the  engine  from  the  rails ;  and  depends  in  amount 
upon  the  ratio  between  the  stroke  and  length  of  connecting 
rod.  Rocking1  laterally,  arising  from  the  difference  of  time 
of  action  of  the  cross  heads ;  one  acting  with  its  greatest 
vertical  power,  when  the  opposite  one  acts  with  none. 
Vibration  in  plan  about  the  centre  of  gravity  of  engine,  pro 
duced  by  the  pressure  between  the  piston  and  crank  pin, 
and  by  the  momentum  of  the  reciprocating  machinery. 
This  last,  combined  with  lateral  rocking,  produces  sinuous 
or  spiral  motion. 

The  amounts  of  these  several  irregularities  depend  con 
siderably  upon  the  arrangement  of  carriage ;  that  is,  upon 
the  position  of  wheels ;  being  less  as  the  base  included  by 
the  bearing  points  is  greater. 

The  influence  of  the  state  of  the  rails  is  shown  by  the 
vertical  and  lateral  shocks  arising  from  the  rail  joints  and 
from  bad  adjustment,  both  horizontally  and  vertically. 

The  amounts  of  these  irregularities  increase  very  rapidly 
with  the  speed.  Le  Chatelier's  experiments  make  them 
increase  nearly  as  the  square  of  the  velocity. 

Longitudinal  fore  and  aft  motion  is  nearly  balanced  by 
applying  a  counterweight  to  the  wheel,  opposite  the  point 
to  which  the  connecting  rod  is  attached.  The  remedy  for 
pitching  consists  in  placing  the  guide  bars  under  the 
heaviest  part  of  the  engine ;  by  which,  a  great  weight  is 
opposed  to  the  vertical  action  of  the  cross  heads.  Cramp- 
ton's- engine  is  quite  free  from  this  disturbance,  as  the  guide 
bars  are  almost  directly  under  the  centre  of  gravity. 

The  'only  counteracting  effort  (remedy  it  is  not)  for  sinu 
ous  motion  yet  applied,  is  extension  of  wheel  and  flange 
base,  thus  giving  the  guiding  wheels  more  control  over  the 
mass  of  the  engine. 

The  remedy,  however,  which  applies  at  once  to  all  of  the 

30* 


354  HANDBOOK   OF  KAILROAD   CONSTRUCTION. 

erratic  movements,  is  reduction  of  speed,  as  when  we  divide 
the  velocity  by  two  we  decrease  the  disturbances  nearly 
fourfold. 


KEVIEW    OF    THE    FORMULA    AND    FORMATION    OF    THE 

TABLES. 

No.  1. 

348.    Given  the  weight  and  velocity  of  a  train,  to  find 
the  necessary  traction  on  a  level. 

Formula. 


W  being  the  weight  of  the  train  in  tons,  and  R  the  resist 
ance  in  Ibs.  per  ton  ;  found  by  the  formula 


By  this  formula  is  formed  table  1,  giving  the  traction  re 
quired  to  move  trains  of  from  fifty  to  one  thousand  tons 
weight,  at  speeds  from  ten  to  one  hundred  miles  per  hour. 

No.  2. 
349.    To  find  the  traction  due  to  a  grade. 

Formula. 

W.R 
~L~> 

where  W  is  the  weight  of  the  train  in  tons,  R  the  rise, 
and  L  the  length  of  the  incline.  By  this  rule  is  formed 
table  2,  giving  the  necessary  traction  to  overcome  grades 


EQUIPMENT.  355 

from  ten  to  one  hundred  feet  per  mile,  with  loads  from  one 
to  one  thousand  tons. 

To  obtain  the  whole  traction  required,  add  the  amounts 
taken  from  tables  1  and  2  ;  thus  the  traction  necessary  to 
draw  five  hundred  tons  at  twenty  miles  per  hour  over  fifty 
feet  grades  is, 

By  table  1,        .....         6,300  Ibs. 
By  table  2,    .         ...,:  >  .  „  .,  r        .  10,605  « 

In  all,        ......       16,905  « 

or,  algebraically, 

(TX7  T?\ 
-77)  =T' 

the  letters  standing  for  the  same  quantities  as  above. 

y 

No.  3. 
350.    To  find  the  weight  to  place  on  the  driving  wheels. 

Formula. 

6  T, 
where  Tis  the  whole  tractive  power.     (Table  3.) 

Nos.  4  and  5. 
The  tractive  power  of  an  engine  is  expressed  by 


Where  Tls  the  tractive  power. 

P,  steam  pressure  in  Ibs.  per  square  inch. 
S,  stroke  in  inches. 
(7,  circumference  of  wheel  in  inches. 
A)  area  of  one  piston  in  inches. 


356  HANDBOOK   OP  RAILROAD   CONSTRUCTION. 

From  this  formula  we  get  the  values  of  the  several  factors 
as  follows :  — 

TO 

The  steam  pressure,  or  P=  ,~  A\  o  <? 

O  T 
The  stroke,  or  S= 


T  C 
The  piston  area,  or  A  =  .  ~  p  .  (C.) 

2  A .  P.  2  S 

The  wheel  circumference,  or  C= ^ .        (D.) 

And  from  (C)  we  get  the  diameter  of  piston  by  the  fol 
lowing  :  — 

,         /  area 
=V.786i- 

And  in  like  manner  from  (D)  the  diameter  of  wheel  by 
d  = 


3.1416' 
(See  tables  4  and  5.) 

No.  7. 

351.    To  find  the  capacity  of  cylinders  of  any  dimension. 
Formula. 

D 2X- 7854  X  Stroke 
1728 

This  gives  the  capacity  in  cubic  feet.      The   dimensions 
above  (see  D  arid  S)  being  in  inches.     (Table  7.) 


EQUIPMENT.  357 

No.  6. 

352.  To  find  the  hourly  steam  consumption  in  terms  of 
the  capacity  of  one  cylinder,  (that  is,  the  number  of  cylin- 
derfuls  per  hour). 

Formula. 

5280 
N~  X  4, 

where  N  is  the  number  of  miles   per   hour,  c  the   wheel 
circumference.     (Table  6.) 

No.  8. 

353.  Knowing  the  hourly  consumption  of  steam,  to  re 
duce  it  to  water. 

Formula. 
B 


B  being  the  bulk  of  steam  in  cubic  feet,  and  N  the  rela 
tive  volume  of  steam  and  water.  (The  values  of  N  are 
given  in  table  8.) 

No.  9. 

354.   Knowing  the  hourly  water  consumption,  to  find  the 
grate  area  and  heating  surface. 

Cubic  feet  of  water  per  hour 
Jb  irst,  r-^ =  grate  area  in  square  ft. 

Second,  S—  ^acX  2 1.2 Cheating  surface, 

where  a  is  the  grate  area,  and  c  the  hourly  consumption 
of  water  in  cubic  feet. 


358  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

From  the  same  formula, 
Grate  area,  or 

5 


Also  water  consumption,  or 


(See  table  9.) 

No.  10. 

355.  To  find  the  necessary  number  of  tubes  to  give  any 
amount  of  heating  surface. 

Formula. 
N-    S 

•*•*  —  ~T    j       > 

Ldn' 

when  Nis  the  number,  S  the  required  surface,  L  the  length, 
d  the  diameter,  both  in  feet,  and  rt=:  3.1416.  (See  Ta 
ble  10.) 

No.  11. 

356.  To  find  the  mean  cylinder  pressure  for  any  percent 
age  of  admission. 

Formula. 
13.5y/o  —  28, 

where  a  is  the  percentage  of  admission.     (See  Table  11.) 

As  to  the  internal  arrangement  of  the  barrel  of  the  boiler, 
we  must  of  course  have  the  length  of  tubes  the  same  as  that 
of  the  barrel,  (that  is,  in  the  general  plan  of  boiler,  some 
makers  have  moved  the  back  flue  plate  ahead).  The  length 
of  tubes  will  of  course  be  the  same  as  the  distance  between 


EQUIPMENT.  359 

the  tube  sheets.     The  number  is  governed  by  their  diameter 
and  by  the  proper  clearance,  which  is  found  by  the  formula, 

N  .  &  . 

•  -jr.  in  eighths  of  inches,  or  ^-^  in  inches, 

8 

The  upper  fifteen  to  eighteen  inches  of  the  barrel  must 
be  left  for  steam  room. 


OF   THE    DIAMETER    OF   BARREL. 

357.    To  find  the  diameter  of  a  barrel  to  contain  a  given 
number  of  tubes, 

Represent  the  inside  diameter  of  boiler  by  D, 

Diameter  of  one  tube  d, 

Clearance  between  tubes  c, 

Number  of  tubes  w, 

Sectional  area  of  boiler,  in  inches  A, 

Water  section,  in  inches  B, 

we  shall  have  as  the  area  of  water  room  per  tube, 

(d+c)*, 
and  the  whole  area  of  water  room, 

(d+c)*Xn, 
the  whole  section  of  the  barrel, 


and  the  diameter  of  that  area, 


J854 

£ 

which  is  the  boiler  diameter  in  inches,  to  which  add  -      on 


360  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

each  side,  or  in  all  ^  as  the  room  to  be  left  between  the 
sides  of  the  boiler  and  first  tube. 

The  diameter  finds  its  maximum  limit  in  the  gauge  less 
the  two  half  breadths  of  tire,  and  two  or  three  inches  allow 
ance  for  attachment  to  the  frame  and  other  mechanical 
incidentals.  The  length  must  be  enough  to  carry  the  lead 
ing  wheels  a  sufficient  .distance  from  the  centre  of  gravity 
of  the  engine. 


ADAPTATION  OF  THE  LOCOMOTIVE  ENGINE  TO  THE  MOVE 
MENT  OF  RAILWAY  TRAINS. 

358.    First,  as  regards  the  nature  of  the  traffic. 

There  are  certain  necessary  causes  of  a  bad  application 
of  power  upon  railroads ;  for  example,  when  the  trains  are 
very  much  heavier  in  one  direction  than  in  the  other,  as  we 
are  obliged  to  use  the  same  engine  both  ways,  because 
when  it  arrives  at  one  end  of  the  road  it  must  go  back  to 
start  again.  Where  the  traffic  requires  to  be  worked  chiefly 
up  hill,  we  use  an  engine  much  heavier*  to  ascend  with  the 
load  than  is  necessary  to  descend  without  a  load.  Different 
objects  of  transport  require  different  speeds.  Perishable 
freight,  such  as  ice,  beef,  pork,  cattle,  &c.,  requires  to  be 
moved  in  much  less  time  than  grain,  lumber,  flour,  coal,  and 
manufactured  articles.  As  a  general  thing,  the  difference 
between  the  characters  of  freight  engines,  as  regards  the 
nature  of  the  traffic,  can  be  adapted  only  with  a  view  to 
amount,  disregarding  the  nature. 

With  passenger  traffic,  however,  there  is  a  great  variety 
of  speeds  made  use  of,  and  consequently  may  be  a  greater 
difference  in  the  proportions  of  engines  depending  entirely 
upon  the  nature  of  the  traffic. 


EQUIPMENT.  361 


ADAPTATION  AS  REGARDS  THE  PHYSICAL  CHARACTER  OF 
THE  ROAD. 

The  best  adaptation  of  locomotive  power  to  any  system 
of  grades,  would  be  that  which  should  render  the  mileage 
a  minimum ;  and  this  will  be  done,  as  nearly  as  possible, 
by  applying  engines,  the  strength  of  which  shall  be  propor 
tional  to  the  resistance  to  be  overcome.  The  best  mode  of 
comparing  different  adaptations  of  power  is  by  reducing 
the  grades  to  a  level ;  or  by  equating  for  grades  by  means 
of  the  capacity  of  motive  power. 

This  is  done  as  follows :  — 

The  length  of  an  incline  being      .      '  .         .'        .  Z, 
The  resistance  on  a  level  being         .         .         .         .  R, 
The  ratio  of  the  resistance  due  to  the  grade  to  the  re 
sistance  on  a  level  by            .         .         .         .  r, 
The  equivalent  horizontal  length  by          ...  Lf, 

and  we  shall  have, 


Example.  —  Let  the  length  of  a  grade  be  seventy-five 
miles  ;  the  value  of 

_R 

and  we  have 


Let  us  now  compare  the  mileage  of  some  of  the  large 
roads  of  America,  as  given  by  a  good,  and  also  by  a  bad 
adaptation  of  power. 

The  Massachusetts  Western  Railroad  may  be  divided 
into  the  four  sections  below  (including  the  Boston  and 
Worcester  road). 

31 


362  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Length          Maximum 
miles.  grade. 

Boston  to  Worcester,     ...        44  30 

Worcester  to  Springfield,  .         .         .     54J  50 

Springfield  to  Pittsfield,          .         .52  83 

Pittsfield  to  Albany,          .        .        .491  45 

Assume  the  speed  of  freight  trains  as  fifteen  miles  per 
hour,  the  resistance  on  a  level  will  be  9.3  Ibs.,  or  for  sim 
plicity  call  it  ten  pounds  per  ton. 

The  resistance  due  to  a  30  feet  grade  is  13  Ibs.  per  ton. 

«                 «         50  "  21  " 

«                «        83  "  35  " 

"                «        45.         "  19  " 

And  the  value  of  r  for  a  30  "  i§  " 

"                "        50  u  f£  " 

"                "        83  "  ff  " 

«                «         45  «  ia  " 

And  the  relative  length  of  the  several  sections  will  be, 


Boston  to  Worcester,  |$  -f-  1§  =  f  £  Of  44   =  101 

Worcester  to  Springfield,  .         .         fi  of  54^  =  169 

Springfield  to  Pittsfield,  .  .         .     f  f  of  52   =  234 

Pittsfield  to  Albany,     .  .         .         f  f  of  49J=  144 


And  the  sums,  200         648 

the  equated  distance  being  3i  times  the  actual  length. 
This  length  assumes  the  resistance  of  the  several  sections 
to  be  for  their  whole  length  that  given  by  their  maximum 
grade.  This  might  seem  erroneous  ;  but  its  correctness  will 
be  seen  when  it  is  remembered  that  the  greatest  load  that 
can  be  taken  over  any  section  is  limited  by  its  maximum 
grade. 

Now  suppose  that  the  engine  employed  is  of  the  fol 
lowing  dimensions  (as  it  is  very  nearly). 


EQUIPMENT.  363 

Cylinders,          .         .         ;-      16  X  20  inches, 
Wheels,         .         .         .        ..  54  inches. 

Assume  the  cylinder   pressure   110  Ibs.,   and  the  tractive 
power  of  the  engine  is  5,287  Ibs. 

A  load  of  500  tons,  upon  a  30  feet  grade,  requires  a 

traction  of       .         .       ',         .         .         .         .  11,500  Ibs. 

Upon  a  50  feet  grade,         .        .....  15,500  Ibs. 

Upon  an  83  feet  grade,  .         .  "      .         .         .         .  22,500  Ibs. 

Upon  a  45  feet  grade,         .        .....  14,500  Ibs. 

To  move  the  above  load  from  Boston  to  Worcester  we 

should  require           ......  2  engines, 

From  Worcester  to  Springfield,    ...         .         .        .  3       " 

"      Springfield  to  Pittsfield,          ....  5       " 

"      Pittsfield  to  Albany,            .....  3       « 

And  the  products  of  the  number  of  engines  by  the  lengths 
of  the  corresponding  divisions,  are 

Boston  to  Worcester,        .  .         44    X  2  =   80 

Worcester  to  Springfield,  .         .     54£  X  3  =  103J 

Springfield  to  Pittsfield,    .  .         52    X  5  =  260 

Pittsfield  to  Albany,     .  .         .     49J  X  3  =  148J 

660 

Suppose  that  by  making  the  engines  on  the  several  sec 
tions  strong  in  proportion  to  the  resistance  of  those  sections, 
one  engine  is  capable  of  taking  the  whole  load  over  all  of 
the  grades.  The  mileage  becomes  as  follows  :  — 

Boston  to  Worcester,  .         .         44    X  1  —  44 
Worcester  to  Springfield,        .         .     54J  X  1  =  54  J 

Springfield  to  Pittsfield,  .         .         52    X  1  =  52 
Pittsfield  to  Albany,       .         .         .     49  J  X  1  = 


200    miles. 


364  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

The  mileage  before  was       .        .  .      .         660  miles, 
And  the  saving  therefore         .         .        .    400      " 

or  about  70  per  cent,  of  the  first  mileage. 

359.    From  a  recent  report  of  the  New  York  and  Erie 
Railroad  it  appears  that  the  same  power  will  draw 

28  tons  on  the  Western  division, 
80          "          Susquehanna  division, 
85          "          Delaware  division, 
and  20          "          Eastern  division, 

neglecting  the  assistance  required  from  Susquehanna  to 
Deposite.  In  the  following  table  are  given  the  actual 
lengths  of  the  several  divisions,  and  the  sum  of  the  products 
of  three  lengths  both  by  the  relative  and  a  uniform  resist 
ance  on  each. 


Division.  Length. 

Western,           128        128  X  3.04  128  X  1-0  201.12 

Susquehanna,   139        139  X  1-06  139  X  1-0             8.35 

Delaware,         104        104  X  1-00  104  X  1.0              0.00 

Eastern,             88          88  X  4.25  88  X  1-0  286.00 

Sum  of  differences,  555.47  miles, 

that  is,  the  miles  run  by  engines  adapted  to  the  work  on 
the  several  divisions  will  be  555.47  less  than  the  miles  run 
by  engines  not  adapted.  (See  Appendix  F.) 

PENNSYLVANIA    CENTRAL    RAILROAD. 

360.    The  physical  character  of  this  road  is  as  follows  :  — 

Length.        Max.  grades. 

Philadelphia  to  Harrisburg,  .         106  45 

Harrisburg  to  Altoona,    .         .         .131  21 

Altoona  to  Johnstown,       =rt  *K?.J  .-•'•'       48J  92 

Johnstown  to  Pittsburgh,          .        .       78J  53 


EQUIPMENT.  365 

The  value  of  r  will  be  here  V 

45  feet  grades,  .         .                •  .         .         .  ^f 

21  feet  grades,           .         .....  •     -ft- 

92  feet  grades,  .        V       '.     -   .         .         .  f$ 

53  feet  grades,           .:      %      ,  ,"      V        .  .     f£ 

Whence  the  equation, 

106  X  («  +  «)  =  307 
131  X(«  +  A)  =  249 
<«+»)=  208 


Sum,  358  Sum,  1039, 

and  1039  —  358  —  681. 

361.    On  the  Baltimore  and  Ohio  Railroad  we  have, 

Miles.  Max.  grade. 

Baltimore  to  Harper's  Ferry,      .        80  82 

Harper's  Ferry  to  Cumberland,       .     98  40 

Cumberland  to  Raccoon,      .         .         88.2  116 

Raccoon  to  148f  miles,  .         .         .     60.5  40 

148|  miles  to  Wheeling,      .         .         51.3  80 

And  as  before, 


80  X  ft»  +  f*)  =  360 
98  X  («  +  «)  =  265 
88.2  X  («  +  «)  =  520 


Sum  of  Col.  1  =  378,  Sum  of  Col.  3  =  1539  ; 
difference  1161. 

Thus  by  the  most  correct  adaptation  of  power,  upon  the 
above-named  railroads,  the  following  percentages  of  mile 
age  may  be  saved. 

31* 


366  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Massachusetts  Western,  .  ;  .         .  70 

New  York  and  Erie,       .  .  .         .         .  55^ 

Pennsylvania  Central,  .  .    '  . '       .    '  68 

Baltimore  and  Ohio,        .  .  .         .        '.  75 

Of  these  roads  the  Baltimore  and  Ohio  is  that  which  has 
actually  the  best  adaptation ;  and  the  Western  road  of 
Massachusetts  that  which  has  the  worst. 

362.  To  determine  the  actual  dimensions  of  the  engines 
which  should  be  used  upon  any  road,  from  the  tables,  pro 
ceed  as  follows :  —  Let  the  load  be  one  hundred  tons,  the 
maximum  grade  thirty  feet  per  mile,  and  speed  twenty-five 
miles  per  hour. 

Referring  to  the  tables  in  succession  we  have, 

By  table  1,  Traction  for  100  tons,  on  a  level,  at  25  miles 

per  hour,  .......  1,550  Ibs. 

By  table  2,  Traction  for  100  tons,  on  a  30  feet  grade,  1,273    « 

Whole  traction  required,          .         .         .  2,823    " 

By  the  formula,  table  3,  the  weight  upon  the  drivers 

must  be 

2823  X  6=  16938  Ibs.,  or  8  tons. 

By  table  4,  with  a  wheel  five  feet  in  diameter,  and  a 
stroke  of  twenty  inches,  we  have  the  decimal  .2122. 

By  table  5,  the  mean  cylinder  pressure  being  sixty  pounds 
per  inch,  and  piston  twelve  inches  in  diameter,  we  have  as 
the  total  pressure 

On  both  pistons,     _.     ;^_^...         .         13,572  Ibs. 
And  finally,  13572  X -2122  =    ','»  .      •       2,880    « 
The  requirement  being      .        > ./_,     .  2,823    " 

By  table  6,  we  see  that  five  feet  wheels  at  twenty- five 
miles  per  hour,  use  33,600  cylinders  of  steam  per  hour. 
By  table  7,  the  capacity  of  a  cylinder  12  X  20  is  1.31 


EQUIPMENT.  367 

cubic  feet;  also  33600  X  1.31  =  44016  cubic  feet  of  steam 
per  hour. 

Assuming  the  mean  cylinder  pressure  at  sixty  pounds, 
and  the  entering  pressure  at  eighty  pounds,  also  the  loss  in 
passing  from  the  boiler  at  twenty  pounds,  we  must  generate 
the  steam  at  one  hundred  pounds  per  square  inch. 

By  table  8,  we  see  that  when  steam  is  produced  under 
one  hundred  pounds  pressure  per  inch,  each  cubic  foot  of 
water  makes  293  cubic  feet  of  steam  ;  whence 


293   • 

is  the  number  of  cubic  feet  of  water  to  be  evaporated  per 
hour.  At  sixteen  cubic  feet  of  water  per  hour  per  square 
foot  of  grate,  we  thus  require 

15.0 

—  -  or  9.4  feet,  nearly  ; 

and  by  table  9,  we  find  the  heating  surface  necessary  to 
evaporate  150  cubic  feet  of  water  per  hour,  with  nine  square 
feet  of  grate  surface,  to  be  779  square  feet  ;  and  by  the  for 
mula,  with  9.4  square  feet,  we  have, 


S=  y/  9.4  X  150  X  21.2  =  797  square  feet, 

the  fuel  being  coke ;  for  wood,  multiply  the  grate  area  (as 
mentioned  before)  by  1.4  and  the  grate  area  will  be  1.4  X 
9.4  =  13.16.  The  tube  surface  of  course  remains  the  same, 
as,  when  the  necessary  amount  of  heat  is  developed,  the 
same  surface  only  is  enough  to  apply  it  to  the  water. 

To  obtain  779  square  feet  of  heating  surface,  we  see,  by 
table  10,  that  it  is  given  by 

100  tubes  17    feet  long  and  1J  inch  diameter, 
or  100     "16  «  If  " 


368  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

or  100  tubes  15    feet  long  and  2    inch  diameter, 

or  100     "  14  "  2|-  " 

or  100     "  121  «  2|  " 

or  100     "  12  "  21  " 

or  by  consulting  the  table,  and  having  given  the  number 
and  length,  the  number  and  diameter,  or  the  length  and  di 
ameter,  we  may  easily  find  the  third  factor  of  the  surface. 
Thus  the  length  being  eleven  feet,  and  diameter  two  inches, 
779  feet  is  obtained  by 

779 

=  135  tubes. 


11X3.1416X167 

To  obtain  the  diameter  of  barrel  to  contain  135  two  inch 
tubes,  we  use  the  formula 


.7864 

We  have  already  found  d=2  inches,  w  — 135,  whence  c 

will  be  by  formula, 

_N_ 

and 
also, 

and 

135X6.45  =  871  +  ; 

and  allowing  three  fourths  of  the  boiler  cross  section  to  be 
filled  with  tubes,  we  have, 

$  of  871  =  1161; 
also, 

$&=»».    • 

the  square  root  of  which  is  38.5  nearly,  to  which  add  ^^ 


EQUIPMENT.  369 

or  4.8  inches,  (see  page  359),  and  we  have 
38.5  -\-  4.8  =  43.3  inches, 

as  the  inside  diameter  of  boiler,  whence  the  following  loco 
motive  to  meet  the  requirement  as  stated. 

Weight  upon  driving  wheels,      16,938  Ibs., 

Cylinders,          .,       .         .         12  X  12  inches, 

Wheels,        .        .        .        .     5  feet, 

Tubes,      .        .        .        .         135  —  11  feet  X  2  inches, 

Grate,          .         .         .         .13.16  square  feet, 

Barrel,  (inside  diameter,)  43.3  inches, 

and  under  the  most  favorable  circumstances,  the  chimney 
may  be  40  inches  high,  12.7  inches  in  diameter ;  the  blast 
orifice  5.8  inches  in  diameter ;  and  the  capacity  of  smoke 
box  39^  cubic  feet. 

363.  We  may  vary  the  tractive  power  of  an  engine  by 
using  the  steam  at  a  greater  or  less  degree  of  expansion, 
but  the  adhesion  remains  the  same.  If  an  engine  was  built 
able  to  work  a-road  partly  level,  and  partly  on  steep  grades, 
varying  the  power  simply  by  varying  the  expansion,  it 
would  be  unnecessarily  heavy  for  the  easy  parts  of  the  road. 
The  expansive  principle  may  be  advantageously  employed 
in  adjusting  the  power  to  the  difference  of  resistance  on 
any  one  division  of  a  road,  and  also  to  the  varying  load 
which  each  day's  traffic  will  present. 

Suppose  we  would  move  a  load  of  two  hundred  tons 
over  the  road  below ;  and  suppose,  also,  that  we  require  the 
cylinder  pressures  set  opposite  the  several  divisions. 

10  miles,  level, 60  Ibs., 

"  10  feet  per  mile,  .  .  .  80  " 
"  20  "  ...  100  " 
«  30  "  120  " 


370  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

The  boiler  pressure  being  150  Ibs.,  and  the  pressure  at 
entering  the  cylinder  145  Ibs., 

An  admission  of  71  per  cent,  gives  a  mean  pressure  of  120  Ibs., 

100  « 
80  « 
60  « 

75  feet, 

70  « 

65  « 

60  « 

55  " 

50  « 

45  « 

40  « 

35  « 

30  " 

We  should  work  the  engine  as  follows :  — 

From    0  to  10  miles,  use  the  10th  notch, 
"      10  to  20      "          «         8th     « 
"      20  to  30      "          "         5th     " 
"     30  to  40      «         "         2d      « 


tt 
ft 

55 

40 

tt 
tt 

u 
it 

tt 
tl 

tt 

28 

u 

a 

.  tt 

And  if  the 

1st 

notch 

of  the  sector 

admits, 

u 

2d 

tt 

u 

u 

tt 

3d 

tt 

tt 

it 

tt 

4th 

tt 

tt 

tt 

t( 

5th 

tt 

It 

tt 

it 

6th 

tt 

tt 

tt 

tt 

7th 

tt 

tt 

tt 

it 

8th 

tt 

tt 

tt 

tt 

9th 

tt 

It 

tt 

tt 

10th 

tt 

tt 

tt 

EQUIPMENT. 


371 


APPLICATION  OF  LOCOMOTIVE  ENGINES  TO  RAILKOADS. 
364.     Department  1.     Freight. 

GENERAL    CLASSIFICATION. 


Number  of 
division. 

Maximum 
grades. 

tl 

Order  1 
60  tons. 

<M  g 

CO  g 

|1 

ig 

«o  § 

Grate  area. 

• 

Tube  surface. 

1 

1 

Cylinders. 
Wheels. 

Weight. 

2 

if 

0   ^ 

3 

*»  ,2 

4 

&'s 

H 

5 

|| 

0  o3 

6 

If 

8  8. 

7 

«S  "3 

Ss 

372 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


The  speed  is  assumed  from  twelve  to  fifteen  miles  per 
hour.  The  mean  cylinder  pressure  is  assumed  at  sixty  Ibs. 
per  square  inch ;  the  initial  pressure  at  ninety  pounds,  and 
the  boiler  pressure  at  120  Ibs.  per  square  inch.  The  grate 
areas  are  designed  for  coke ;  for  wood  multiply  the  same 
by  1.4. 

365.     Department  2.     Passenger. 


Classification. 

Order  1 
50  tons. 

Order.  2 
100  tons. 

Order  3 
150  tons. 

Order  4 
200  tons. 

Designation 
of  parts. 

1-4 

1S 

25  miles 
per  hour. 

Grate  area. 
Tube  surface. 
Cylinders. 
Wheels. 
Weight. 

Division  2 
20'  grades. 

11 

Division  3 
40'  grades. 

It 

SI 

h 

25  miles 
per  hour. 

Division  5 

&y  grades. 

!{ 

l| 

H 

EQUIPMENT.  373 

The  engines  in  the  Northern  States  require  more  power 
in  winter  than  in  summer. 

To  the  above  classification  might  be  added,  an  engine 
for  "  making  up  trains,"  and  similar  station  work ;  such  an 
engine  should  be  able  to  start  easily  the  extreme  weights 
of  trains,  from  fifty  to  one  thousand  tons,  and  should  be 
fitted  with  a  power  of  varying  its  adhesion. 

32 


374  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FORMULA. 


[V 

Example. 
The  speed  being  thirty  miles  per  hour,  and  load  250  tons. 

R  will  be  [^yr5  +  8]  X  250  =  3315  Ibs. 


EQUIPMENT. 


375 


366.  Table  1.  Showing  the  required  traction  on  a  level 
for  loads  from  fifty  to  one  thousand  tons,  and  for  velocities 
from  ten  to  one  hundred  miles  per  hour. 


Ve 
locity. 

50 
Tons. 

75 

Tons. 

100 

Tons. 

250 
Tons. 

500 
Tons. 

750 
Tons. 

1000 
Tons. 

10 

429 

643 

858 

2146 

4292 

6435 

8585 

12 

442 

663 

884 

2210 

4421 

6630 

8842 

15 

465 

698 

931 

2328 

4657 

6982 

9315 

20 

517 

773 

1034 

2585 

5170 

7735 

25 

582 

874 

1165 

2912 

5825 

30 

663 

994 

1326 

3315 

6630 

40 

868 

1302 

1736 

4340 

50 

1131 

1696 

2262 

5655 

60 

1452 

2180 

2905 

100 

3324 

4986 

6648 

376  HANDBOOK   OF  RAILROAD   CONSTRUCTION 


FORMULA. 

WR 
L    * 

Example. 

The  tractive  power  to  overcome  the  resistance  of  750  tons 
upon  a  sixty  feet  grade  is 

750  x  Jo-19090- 


EQUIPMENT. 


377 


367.  Table  2.  Showing  the  tractive  power  necessary  to 
overcome  grades  from  ten  to  one  hundred  feet  per  mile  with 
loads  from  one  to  one  thousand  tons* 


Grade. 

1 

Ton. 

50 
Tons. 

75 
Tons. 

100 
Tons. 

250 
Tons. 

500 
Tons. 

750 
Tons. 

1000 
Tons. 

Grade. 

10 

4 

212 

318 

424 

1061 

2121 

3181 

4240 

10 

20 

8 

424 

636 

848 

2122 

4242 

6362 

8480 

20 

30 

13 

636 

955 

1273 

3170 

6363 

9545 

12730 

30 

40 

16 

848 

1272 

1696 

4244 

8484 

12724 

16960 

40 

50 

20 

1060 

1590 

2120 

5305 

10605 

15905 

21200 

50 

60 

26 

1272 

1910 

2546 

6340 

12726 

19050 

25460 

60 

70 

30 

1500 

2240 

3000 

7500 

15000 

22400 

30000 

70 

80 

33 

1697 

2545 

3393 

8489 

16969 

25459 

33950 

80 

100 

40 

2120 

3180 

4240 

10610 

21210 

31810 

42400 

100 

Grade. 

1 

Ton. 

50 
Tons. 

75 
Tons. 

100 
Tons. 

250 
Tons. 

500 
Tons. 

750 
Tons. 

1000 
Tons. 

Grade. 

32* 


378  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FORMULA. 
QT. 

Example. 

Required   traction   5,000  Ibs. ;   upon   driving   axles   the 
weight  is  5000  X  6  =  30,000  Ibs. 


EQUIPMENT. 


379 


368.  Table  3.  Giving  the  weight  which  should  be  placed 
upon  the  driving  axles  to  secure  any  amount  of  adhesion  ; 
the  latter  being  one  sixth  of  the  weight. 


Required  traction. 

Weight  in  pounds. 

Weight  in  tons. 

500 

3000 

1.34 

1000 

6000 

2.69 

2000 

12000 

5.36 

3000 

18000 

8.04 

4000 

24000 

10.80 

5000 

30000 

13.40 

6000 

42000 

16.07 

7000 

42000 

18.75 

8000 

48000 

21.43 

9000 

54000 

24.11 

10000 

60000 

26.80 

12000 

72000 

32.14 

14000 

84000 

37.50 

16000 

96000 

42.86 

18000 

108000 

48.22 

20000 

120000 

53.60 

380  HANDBOOK   OP   RAILROAD   CONSTRUCTION. 


FORMULA, 

2(8 

c 

Where  S=z  stroke. 

c  =  circumference  of  wheel,  (both  in  inches.) 

Example. 

Let  stroke  be  twenty  inches,  and  diameter  of  wheel  five 
feet,  the  ratio  will  be 

•  40 

=  0.2122. 


188.4 


EQUIPMENT, 


381 


369.  Table  of  decimals,  which,  multiplied  by  the  total 
piston  pressures  (table  5)  will  give  the  traction  in  pounds, 
or  ratio  between  double  stroke  and  wheel  circumference. 
Table  4. 


STROKE  IN  INCHES. 

g 

18 

20 

22 

24 

26 

28 

30 

32 

34 

36 

' 

3^ 

2728 

3031 

3334 

3638 

3* 

8| 

2553 

2837 

3120 

3404 

3688 

8| 

4 

2386 

2652 

2918 

3182 

3444 

3708 

4 

** 

2250 

2500 

2750 

3000 

3250 

3500 

3750 

4i 

4£ 

2151 

2390 

2593 

2830 

3071 

3294 

3529 

3764 

4* 

4 

2012 

2235 

2459 

2682 

2905 

3129 

3352 

3575 

3800 

4f 

5 

1910 

2122 

2334 

2546 

2766 

2979 

3192 

3405 

3617 

3830 

5 

5* 

1736 

1929 

2122 

2315 

2500 

2692 

2885 

3077 

3273 

3473 

5* 

6 

1591 

1768 

1945 

2122 

2321 

2500 

2678 

2857 

3036 

3215 

6 

*i 

1468 

1632 

1796 

1958 

2131 

2295 

2459 

2623 

2790 

2951 

** 

7 

1364 

1516 

1667 

1819 

1970 

2121 

2273 

2424 

2576 

2727 

7 

H 

1272 

1414 

1556 

1691 

1831 

1972 

2114 

2254 

2394 

2535 

H 

8 

1194 

1326 

1417 

1592 

1688 

1818 

1948 

2078 

2208 

2337 

8 

18 

20 

22 

24 

26 

28 

30 

32 

34 

.36 

1 

1 

STROKE  IN  INCHES. 

382  HANDBOOK  OF  RAILROAD  CONSTRUCTION, 


FORMULA. 


Where  d=  diameter. 

p  —  pressure  per  inch. 

Example. 

The  whole  pressure  at  one  hundred  pounds  per  inch  on 
two  sixteen  inch  pistons  will  be 

2  [16  X  16  X  0.7854  X  100]  =  40212. 


EQUIPMENT. 


383 


370.  Table  5.  Total  pressures  upon  pistons  from  ten  to 
twenty-four  inches  in  diameter,  and  for  steam  pressures 
from  fifty  to  one  hundred  and  fifty  pounds  per  square  inch. 


£g 


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O5O5C5Oi-<|COI—  '  O3  OS  O  OS  -<1  H-  'Oil—  ' 
CS03^COOC3tOO'CO^O>-'^.lC5CO 
•^irf^-hSO-^lOOOiwiO-^I^OOiCSOGO 
tCOGOtOCiOOOOCOSlOOSGOOO 


oooooo 


^a  i 


384  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FORMULA. 


Where  N=  the  number. 

c  —  wheel  circumference. 

Example. 

Speed  twenty-five  miles  per  hour,  wheels  four  and  a  half 
feet,  the  number  of  cylinders  per  hour  is 

5280        X  4  =  37300. 


4J  X  3.1416 


EQUIPMENT. 


385 


371.  Table  6.  Showing  the  hourly  consumption  of  steam 
in  terms  of  the  capacity  of  one  cylinder,  with  wheels  from 
three  and  a  half  to  eight  feet,  and  speeds  from  ten  to  sixty 
miles  per  hour. 


-? 

d 

Si 

h 

59 

NUMBER  OF  CYLINDERS  PER  HOUR  AT  A  VELOCITY  OF 

z 
a 

*•§ 

g  a 

£"* 

1* 

10 

12 

15 

20 

25 

30 

40 

50 

60 

;u 

42 

480 

19200 

23040 

3| 

45 

449 

17960 

21552 

26940 

4 

48 

421 

16840 

20208 

25260*33681 

•H 

51 

397 

15880 

19056 

23820:31760 

39700 

4i 

54 

373 

14920 

17904 

22380  29840 

37300 

4^ 

57 

361 

14440 

17328 

21660|28880 

36100 

5 

60 

336 

20160  26880 

33600 

5i 

66 

306 

1836024480 

30600!36720 

6 
6* 

72 
78 

281 
259 

|22480 
20720 

281003372044960 
259003108041440 

51800 

62160 

7 

'£ 

84 
90 

240 

224 

19200 

24000 
22400 

288003840048000 
208808584044800 

57600 
53760 

8 

96 

211 

21109 

25320'33760 

42200 

50640 

, 

J 

386  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FORMULA. 

Z»2.7854X  Stroke  _n 
1728 

Example. 
Cubic  content  of  a  cylinder  15  X  24  is 


1728 


EQUIPMENT. 


387 


372.  Table  7.  Capacity  of  cylinders  in  cubic  feet  of 
from  ten  to  twenty-four  inches  in  diameter,  and  from  eigh 
teen  to  thirty-six  inches  stroke. 


Diam. 

CAPACITY  OF  CYLINDERS  IN  CUBIC  FEET,  STROKE  BEING 

Diain. 

of 

of 

cyl'r. 

18 

20 

22 

24 

26 

28 

30 

32 

34 

36 

cyl'r. 

10 

082 

091 

100 

109 

118 

127 

136 

145 

10 

11 

093 

104 

115 

126 

137 

148 

159 

170 

181 

11 

12 

118 

131 

144 

157 

170 

183 

196 

209 

222 

235 

12 

13 

133 

149 

165 

181 

197 

213 

229 

245 

261 

277 

13 

14 

160 

178 

196 

214 

232 

250 

268 

286 

304 

322 

14 

15 

184 

204 

224 

244 

264 

284 

304 

324 

344 

364 

15 

16 

208 

232 

255 

278 

301 

324 

347 

370 

393 

416 

16 

17 

235 

263 

289 

315 

341 

367 

393 

419 

445 

471 

17 

18 

263 

294 

323 

352 

381 

410 

439 

468 

497 

526 

18 

19 

361 

394 

427 

460 

493 

526 

559 

592 

19 

20 

400 

437 

474 

511 

548 

585 

622 

659 

20 

21 

481 

521 

561 

601 

641 

681 

721 

21 

22 

528 

572 

616 

660 

704 

748 

792 

22 

23 

.625 

674 

723 

772 

821 

876 

23 

24 

681 

733 

785 

837 

889 

941 

24 

EQUIPMENT. 


389 


373.    Table  8.    Giving  the  volume,  pressure,  temperature, 
and  density  of  steam. 


Steam 
pressure. 

Relative  vol 
ume  or  cubic 
feet  of  steam, 
water  being  1. 

Temperature. 

Total  heat. 

Weight  of  a 
cubic  foot. 

Steam 
pressure. 

50 

552 

281 

1200 

1129 

50 

60 

467 

293 

1203 

1335 

60 

65 

434 

298 

1205 

1436 

65 

70 

406 

303 

1206 

1535 

70 

75 

381 

307 

1208 

1636 

75 

80 

359 

312 

1209 

1736 

80 

90 

323 

320 

1212 

1929 

90 

100 

293 

328 

1214 

2127 

100 

110 

269 

335 

1216 

2317 

110 

120 

249 

341 

1218 

2505 

120 

130 

231 

347 

1220 

2698 

130 

140 

216 

353 

1221 

2885 

140 

150 

203 

358 

1223 

3070 

150 

33 


390  HANDBOOK   OF  RAILEOAD   CONSTRUCTION. 


FORMULA. 


Where  S  =  surface. 

a  =  grate  area. 
c  =  cubic  feet  of  water  per  hour. 

Example. 

Grate  area  sixteen  square  feet,  cubic  feet  of  water  per 
hour  two  hundred,  surface  is 


V/16X  200  X  21.2  =  1199.92. 


EQUIPMENT,  391 

374.  Table  9.  Showing  the  necessary  amount  of  grate 
area  and  heating  surface  for  any  hourly  consumption  of 
water. 


cnioo 

O  Cn  O 


I  Cubic  ft.of  water 
jevap'd  per  hour. 


oi  05  a  O5  en  en 

OO  C5   CO  H«l  OO  O5 
05  CO  CO  *•  00  h-l 


1  ~J  ~J  -O  05  05  05  en 

:Cn  co  o  oo  en  to  CD 
oo  *>•  to  co  -T  oo  co 


O  O  CD  CO  CO  CD  OO 
l-i  O  -J  >f>-  U)  O  -T  I 

co  o  >*»•  oo  *«.  o  >*>. 


OO  OO  06  60  •*  •<!  -4 
00  O5  CO  O  -J  CO  O 

CD  o  \»  H*  o  ~j  co 


O  O  O  CO  CD 

os  co  h-i  oo  en 
h^  co  co  en  ^i 


co  CD  oo  oo  oo  -<r 

td  O  O5  CO  O  -J 

~J  O  CO  -<l  Cn  O  > 


COtOtOtOtOl— i  h-i  I-* 

o-jencoooocnco' 

tOCDOStOOOrf^CDCO' 


1  tS  tO  IO  tO  I-*  i 
-*J  en  to  O  «J  i 
QO  rfi.  CD  CO  O5 


§CD  CD  CD  OO 
-J  CO  O  O5 


*.  co  co 

O  ~1  ttk.  i 
O  rf»-  CD  i 


to  to  to  to 

oo  to  en  -j 


(_l  |_>  H-«  t-4  O 

oo  05  co  o  -<r 

CO  h-i  tC  U)  l-i 


td  05  O  H-l  H-" 


co  to  td 

»-»  oo  en  i 


•  o  o  o  co  co 
>  rT  Co  o  C5  U) 

co  oo  co  en  "^i 


C5  O5  Cn  en  *>  *»  »*»  4*  CO  ' 


1  M  *>.  O5  en  CO  O 


So  o 
-<r  co 

05  O  rfk 


•  -^  ^r  os  os  ox 


§ht^ 
^T 

to  01  oo  ' 


O  CD  CO  i 

10  oo  rf>.  • 
en  en  co  i 


en  en  en 
'  CO  O5  en 


rf».  rfv  rfi.  co  co 
oo  en  co  co  os 
>^  oo  i"  oo  en 


o  co  CD 

K-i  05  tO 

co  co  t*^ 


OCOi&OOOC-<TOSO5O5Cnen 
l-'enOrf».Orfi.CO*>t-iOOO< 


:g 


co  co  to  to  i-i  >-•  h-i 


O  OO  O  OO  OS 


111 


h-»  O  O  CD 
O  05  I—  ^ 
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»-*  I-1  O  CD  CO 
«<T  tO  en  CD  CO 

en  o  05  o  oo 


OO  CO  -3  tO  CD  ' 
05  CO  00  tO  CO, 


CO  CO  tO  tO  tO  I— i 
-<I  CO  CO  en  h-i  •<! 
O  rf*.  OS  OO  OO  ~T 


CO  00  *.  CO 

co  co  to  en 


•<r  *«.  to  oc 


I-*  en  CO  Cn  CO  CD  • 

en  co  co  rf^-  oo  to  < 


O5  O5  en  en  en  >^.  tf». 
rf».  O  --T  rf>-  O  O5  CO  i 

to  co  en  t-i  en  oo  i-i  i 


co  to  to 

l-i  -<I  to 

rf^  tO  CD  I 


i-i  oo  en  to  ~j  to  os 


en^i^^cocotototOH-ti— >o 
cocoostooo^coenoosHiOs 
oscOi~itot>oi-'oo4>.ootot-'o 


co  CD  oo  oo 

;co  co  ~^  t^.  ' 
CO  tO  tO  h-»  ' 


•"»  CO  O  OS  tO  ' 


O  CD  CD  OO  OO 
CO  -^  O  "<f  rf>-  • 

to  o  i^-  co  to 


'  ~^  05  O5  O5  en  en  en  i 

'  CO  CC  O5  CO  CO  Cn  H*  ' 

co  to  Co  rf».  05  oo  oo 


co  co 

;co  en 
co  o 


CO  tO  tO  h->  h-l 

o  en  o  en  o 
co  en -*  en  to 


c 

K^  4-  C£ 

— T 


co  CD  oo  oo 

Z  —  -  !  .i. 

i  CO  O  ^1  CO 


-<r  co  o  05  to  oo  ^ 
rf».  oo  i-i  >*>.  en  C5  os 


»**.  co  co 

t-i  -~I  tO 

CD  CO  «^I 


oo  co  os  to 


G'  4-  4-  CO  1C  1C  ( 
Cn  O  -<f  CO  rf^  05 


O  O  CO  CD  CO  CO 
CO  tO  OS  CO  >— l  --^ 

os  rf».  oo  co  o  en 


CO  CO  CO  tO  ha  h-. 


05  en  *»  co  co  to 

o  to  en  <c  to  Oi 

00  CO  CD  C5  tO  *-  t 


•»»  -<r  os  02  os  en  en 

h-^  tO  CO  IO  O  00  rf>. 


>*»*-  co  co  to  tc  i— > 

O5  tO  «<l  tO  --I  Hi  O5 

co  to  *>.  co  to  ->?  i— 


392  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


FORMULA. 

S  S 


=  Tcht™ 

Where  S=z  whole  surface, 
"      L  =  length, 
"      d  =  diameter,  in  feet, 
"      n  =3.1416, 
"      N=zthe  number. 

Example* 

Diameter  two  inches,  surface  1466,  length  fourteen  feet, 
we  have, 

1466 

N—  14X0.167X3.1416  ~~ 


EQUIPMENT, 


393 


375.    Table  10.     Giving  the  number  and  dimensions  of 
tubes  to  obtain  any  given  amount  of  surface. 


L'gth. 

Diam. 
1* 

Diam. 

l! 

Diam. 
11 

Diam. 
2 

Diam. 
2* 

Diam. 

241 

Diam. 

9 

Diam. 

aj 

L'gth. 

8 

314 

336 

397 

419 

445 

471 

504 

523 

8 

8£ 

334 

389 

422 

445 

473 

500 

535 

556 

8£ 

9 

352 

411 

447 

471 

507 

530 

566 

588 

9 

H 

372 

435 

471 

497 

523 

559 

597 

621 

H 

10 

392 

457 

496 

524 

556 

589 

628 

655 

10 

10* 

411 

480 

521 

549 

584 

618 

659 

687 

1°* 

11 

431 

503 

545 

576 

612 

647 

690 

720 

11 

ill 

451 

526 

570 

602 

640 

677 

721 

753 

u* 

12 

471 

549 

595 

628 

667 

705 

752 

786 

12 

1*J 

490 

572 

620 

654 

695 

735 

783 

818 

12£ 

13 

510 

595 

645 

681 

723 

764 

814 

851 

13 

13$ 

530 

617 

669 

707 

750 

793 

845 

884 

13£ 

14 

549 

640 

695 

733 

778 

823 

876 

916 

14 

M$ 

569 

663 

719 

759 

806 

852 

907 

949 

14i 

15 

589 

686 

744 

785 

834 

882 

938 

982 

15 

15| 

608 

708 

769 

811 

861 

911 

969 

1015 

15£ 

16 

628 

731 

794 

837 

889 

941 

1000 

1048 

16 

16$ 

648 

754 

819 

863 

917 

971 

1031 

1081 

16£ 

17 

668 

777 

843 

889 

945 

1000 

1062 

1114 

17 

394  HANDBOOK  OF  RAILROAD  CONSTRUCTION. 


FORMULA. 

13.5y/a  — 28, 
where  a  is  the  percentage  of  admission. 

Example. 

What  is  the  mean  pressure,  with  an  initial  pressure  of 
one  hundred  pounds,  and  sixty  per  cent,  admission. 

13.5  ^60  —  28  =  (13.5  X  7.7)  —  28  =  ^  of  100,  or  76  Ibs. 


EQUIPMENT. 


395 


376.  Table  11.  Showing  the  mean  cylinder  steam  pres 
sure  for  any  percentage  of  admission,  the  initial  pressure 
being  from  50  to  150  Ibs.  per  inch. 


Initial 

MEAN  CYLINDER  PRESSURE,  ADMISSION  BEING  IN  HUNDREDTH  S  OF 

pressure 

THE  STROKE. 

in 

pounds. 

10  15 

20 

25 

80 

35 

40 

45 

50 

55 

60 

65 

70 

75 

50 

7 

12 

16 

20 

23 

26 

28 

31 

•  33 

36 

38 

40 

42 

44 

60 

9 

14 

19 

24 

28 

31 

34 

37 

40 

43 

46 

49 

51 

53 

70 

10 

17 

22 

28 

33 

36 

40 

43 

47 

50 

54 

57 

59 

62 

80 

12 

19 

26 

32 

38 

42 

41 

49 

54 

58 

62 

65 

68 

71 

90 

13  22 

29 

36 

42 

47 

51 

54 

60 

65 

69 

73 

76 

80 

100 

15  !  24 

32 

40 

47 

52 

57 

62 

67 

72 

77 

81 

85 

89 

110 

16 

26 

35  44 

52 

57  63 

68 

74 

79 

85 

89 

93 

98 

120 

18 

29 

38 

48 

56 

62  i  68 

74 

80 

86 

91 

97 

102 

107 

130 

19 

31 

42 

52 

61 

68  i  74 

81 

87 

94 

99 

105 

110 

116 

145 

21 

34 

45 

56 

65 

73  :  80 

87 

94 

101 

107 

113 

119 

125 

160 

22 

36 

48 

60 

70 

78  85 

93 

100 

108 

114 

121 

127 

134 

I 

' 

396  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

PART   II. 

CARS. 

WHEELS    AND    AXLES. 

377.  Of  the  mechanical  details  of  car  building  it  is  not 
necessary  here  to  speak  ;  but  of  those  matters  which  fit  a 
car  for  special  duty,  and  depend  upon  particular  character 
istics  of  any  road,  such  as  the  gauge,  something  must  be 
said. 

The  trend  of  the  wheel  tire,  as  remarked  in  Chapter 
XIIL,  is  not  turned  cylindrical,  but  conical.  A  perfectly 
straight  road  would  of  course  require  no  cone  upon  the 
wheels  ;  the  object  of  the  latter  being  to  vary  the  wheel 
diameter  when  upon  curves.  The  general  practice  is  to 
give  a  certain  standard  cone  to  all  wheels,  for  all  gauges. 
This  is  quite  wrong,  as  will  be  seen  by  the  following  for 
mula,  which  is  from  "  Pambour  on  the  Locomotive  Engine." 

156. Let  m  rn'i  fig.  156,  represent  the 

outer  rail,  and  n  ri  the  inner  one. 
The  circumferences  upon  the 
same  axles  must  evidently  vary 
as  the  length  of  these  curves, 
which  are  included  between  the 
same  radii. 

Let  Z>,  be  the  diameter  of  trie 
first  wheel,  and  d,  that  of  the  second  ;  and  we  shall  have, 

mm'       n  D 
nn'  ~  ~  n  d  J 
or  otherwise 

mm'  =  3.1416  Z>, 
and 

«»•'  =  3.1416  rf. 


EQUIPMENT.  397 

We  have  also, 


nn         no 

Expressing  the  radius  of  curvature  by  r,  arid  the  half 
gauge  by  e,  the  above  proportion  may  be  expressed  by 

mm'      r-\-e 
and  also 


and  finally 


This  equation  shows  the  difference  in  diameters  that 
ought  to  exist  between  the  inner  and  outer  wheels,  that  the 
required  effect,  (no  dragging  of  the  outer  and  no  slipping  of 
the  inner  wheel,)  is  produced. 

Example. 

Let  the  radius  of  curvature  be  ...         1,000  feet, 

The  gauge  of  the  road,          .....  6     " 

The  wheel  diameter,        .         .       -v^  -  ^       V   ;  4     " 


And  the  formula  becomes 

2ed         24 


1003 


=  .024  feet, 


or  .288  inch  on  both  wheels,  or  0.144  inch  for  each  wheel ; 
which  for  four  inches  breadth,  gives  a  curve  of  ^  of  the 
width,  or  decimally,  0.144,  and  vulgarly,  |  of  an  inch.  For 
a  three  feet  wheel,  the  rule  gives  a  cone  of  0.11  inch. 

NOTE.  —  Messrs  Bush  and  Lobdel  cone  their  wheels  0.08  inches  in  a  four  inch 
tire ;  or  £  inch  per  foot.  The  formula  above  for  a  three  feet  wheel,  and  4'  8^" 
gauge,  gives  a  curve  of  0.09  inches. 

34 


398  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

The  wheel  most  used  upon  American  roads  is  made  of 
cast-iron,  in  one  piece,  and  consists  either  of  two  side  plates, 
connected  by  a  hub  and  rim,  or  of  a  central  plate  ribbed  on 
the  sides.  Messrs  Whitney  and  Son,  (Philadelphia,)  pass 
all  their  wheels  through  an  annealing  process,  which  renders 
them  much  less  liable  to  fracture  from  shocks  and  from 
cold  than  when  the  wheel  is  allowed  to  cool  at  once,  when 
hot  from  the  foundery. 

The  wheels  used  upon  English  roads  are  made  with  a 
wrought  iron  rim  and  spokes,  with  a  cast  hub,  the  tire  being 
put  on  separately.  Such  wheels  are  less  liable  to  fracture, 
but  cost  more  than  the  American  wheel. 

378.  A  very  frequent  cause  of  accident  upon  railroads,  is 
the  breakage  of  axles.  Experiments  made  at  Wolver- 
hampton,  (England,)  upon  differently  formed  axles,  show 
very  plainly  that  it  is  quite  wrong  to  reduce  the  diameter 
of  the  axle  at  the  middle.  That  if  any  variation  exists  it 
should  be  in  making  the  middle  the  largest.  That  the  effect 
of  a  shoulder  behind  the  wheel  was  to  decrease  very  much 
the  strength.  Probably  the  strongest  and  most  economical 
railroad  axle,  would  be  a  wrought  iron  tube.  Certainly  a 
hollow  axle  is  much  stronger  in  resisting  tension  than  a 
solid  one  containing  the  same  amount  of  material. 

NOTE  1.  —  Thomas  Thorneycroft,  of  Wolverhampton,  England,  an  educated 
man,  and  a  manufacturer  of  railway  axles,  observes  :  —  That  the  various  forms 
of  axles,  as  generally  made,  possess  within  themselves  the  elements  of  destruc 
tion.  That  there  are  certain  fixed  principles  to  be  observed  in  proportioning 
axles,  and  that  just  as  such  principles  are  departed  from,  just  so  much  is  liability 
to  failure  increased. 

He  says  :  —  It  is  doubtful  whether  the  wheel  is  the  support  and  the  journal 
the  loaded  part,  or  the  reverse.  If  the  latter  is  the  case,  then  the  cone  of  the 
wheels  causes  a  lateral  strain,  tending  to  bend  the  axle ;  and  should  that  bending 
extend  no  further  than  one  half  of  the  elastic  limit,  if  long  continued,  fracture 
must  result ;  and  should  the  elastic  limit  be  exceeded,  the  plane  of  the  wheel 
will  be  removed  from  that  in  which  it  ought  to  revolve. 


EQUIPMENT.  399 

The  object  of  the  first  experiment  was  to  determine  the  effect  of  the  form  of 
the  longitudinal  section  of  the  axle  upon  its  elastic  limit. 

By  reducing  the  diameter  of  the  axle  from  4T^  inches  at  centre,  to  3f  inches ; 
the  limit  of  elasticity  was  reduced  from  .343  to  .232  inches ;  and  the  load,  to  pro 
duce  that  elasticity,  from  fourteen  to  seven  tons. 

Experiment  second  was  to  ascertain  the  effect  of  a  reduction  of  diameter  at 
the  centre,  upon  the  ability  to  resist  sudden  shocks.  One  half  of  the  axle  was 
made  4^  inches  in  diameter  from  middle  to  end,  and  the  other  half  was  reduced 
from  4^  to  four  inches  at  centre.  The  wheel  being  fixed,  and  a  ram  allowed  to 
fall  upon  the  journal,  when  the  following  result  was  obtained.  Under  forty-six 
blows,  the  unreduced  end  was  bent  to  an  angle  of  eighteen  degrees.  Under  six 
teen  blows,  the  reduced  end  was  bent  to  twenty-two  degrees. 

Experiment  third  was  to  ascertain  the  effect  of  a  shoulder  behind  the  wheel, 
one  end  being  turned  with  a  shoulder  of  one  eighth  of  an  inch,  as  a  stop  to  the 
wheel,  the  other  end  turned  plain.  Tested  by  hydraulic  pressure,  the  shouldered 
end  broke  with  sixty  tons,  the  plain  end  with  eighty-four  tons. 

The  object  of  the  fourth  experiment  was  to  find  the  influence  of  the  po 
sition  of  the  wheel,  as  regards  the  end  of  the  journal.  An  axle  was  fastened 
into  a  cast-iron  frame,  in  a  line  with  the  neck  of  the  journal,  when  the  latter 
was  broke  with  seven  blows  of  a  ram  falling  ten  feet.  The  other  end  was 
keyed  into  the  frame,  with  the  neck  of  the  journal  projecting  1^  inch,  and  broke 
at  the  twenty-fourth  blow  of  the  same  ram,  falling  ten  feet. 

The  results  of  the  trials  are  thus  summed  up  by  the  experimenter  :  —  That 
axles  should  never  be  smaller  at  the  centre  than  at  the  ends,  but  on  the  contrary, 
that  if  a  difference  in  size  is  made,  the  centre  should  be  the  largest. 

The  best  authorities  on  the  strength  of  materials,  give  the  hollow  tube  as  three 
times  stronger  in  resisting  twisting,  than  the  solid  bar  possessing  the  same  weight. 
Thus  an  axle  with  an  external  diameter  of  five  inches,  and  an  internal  diameter 
of  3|  inches,  is  three  times  as  strong  as  a  solid  axle  of  3|  inches  diameter. 

NOTE  2.  —  The  following  experiments  were  prepared  by  M.  Bourville,  and 
executed  by  the  Austrian  government.  The  apparatus  consisted  of  a  bent  axle, 
which  was  firmly  fixed  up  to  the  elbow  in  timber,  and  which  was  subjected  to 
torsion  by  means  of  a  cog-wheel  connected  with  the  end  of  the  horizontal  part. 
At  each  turn  the  angle  of  torsion  was  twenty-four  degrees.  A  shock  was  pro 
duced  each  time  that  the  bar  left  one  tooth  to  be  raised  by  the  next.  An  index 
adapted  to  the  apparatus,  indicated  the  number  of  revolutions  and  shocks. 
Seven  axles,  submitted  to  this  trial,  presented  the  following  results  :  — 

1st.  The  movement  lasted  one  hour;  10,800  revolutions  and  32,400  shocks 
were  produced.  The  axle,  two  and  six  tenths  inches  in  diameter,  was  taken 
from  the  machine  and  broken  by  an  hydraulic  press.  No  change  in  the  texture 
of  the  iron  was  visible. 


400  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

2d.  A  new  axle,  having  been  tried  four  hours,  sustained  129,000  torsions,  and 
was  afterwards  broken  by  means  of  an  hydraulic  press.  No  alteration  of  the 
iron  could  be  discovered,  by  the  naked  eye,  on  the  surface  of  rupture  ;.  but  tried 
with  a  microscope,  the  fibres  appeared  without  adhesion,  like  a  bundle  of  needles. 

3d.  A  third  axle  was  subjected,  during  twelve  hours,  to  388,000  torsions,  and 
broken  in  two.  A  change  in  its  texture,  and  an  increased  size  in  the  grain  of 
the  iron,  was  observed  by  the  naked  eye. 

4th.  After  one  hundred  and  twenty  hours,  and  3,888,000  torsions,  the  axle 
was  broken  in  many  places ;  a  considerable  change  in  its  texture  was  apparent, 
which  was  more  striking  towards  the  centre ;  the  size  of  the  grains  diminished 
towards  the  extremities. 

5th.  An  axle,  submitted  to  23,328,000  torsions  during  seven  hundred  and 
twenty  hours,  was  completely  changed  in  its  texture ;  the  fracture  in  the  middle 
was  crystalline,  but  not  very  scaly. 

6th.  After  ten  months,  during  which  the  axle  was  submitted  to  78,732,000 
torsions  and  shocks,  fracture,  produced  by  an  hydraulic  press,  showed  clearly  an 
absolute  transformation  of  the  structure  of  the  iron  ;  the  surface  of  rupture  was 
scaly  like  pewter. 

7th.  Finally,  as  a  last  trial,  an  axle  submitted  to  128,304,000  torsions,  pre 
sented  a  surface  of  rupture  like  that  in  the  preceding  experiment.  The  crystals 
were  perfectly  well  defined,  the  iron  having  lost  every  appearance  of  wrought 
iron. 


CLASSIFICATION  OF  CARS. 

379.  Railroad  cars  come  under  three  general  heads, 

Those  for  passenger  transport, 
Those  for  freight  traffic, 
Those  for  repairs  of  the  road. 

380.  The   American   passenger  car  consists  of  a  body 
about  fifty  feet  long,  ten  feet  wide,  and  seven  feet  high, 
containing  seats  for  about  sixty  passengers,  being  cushioned, 
warmed,  lighted,   and  ventilated.      Except  for  emigrants, 
second  and  third  class  cars  are  but  little  used  in  America. 

House,  box,  or  covered  freight  cars,  differ  from  the  "  flat," 
or  platform  car,  only  in  having  a  simple  rectangular  house, 
about  six  feet  high  and  nine  feet  wide,  built  upon  the  floor. 


EQUIPMENT.  401 

This  is  used  for  the  protection  of  such  freight  as  will  not 
bear  exposure ;  as  furniture,  books,  dry  goods,  hardware, 
and  small  machinery.  Carriages,  boxes,  bales,  masts,  lum 
ber,  and  fuel  are  carried  by  platform  cars.  Bulky  machin 
ery,  and  first  and  second  class  freight  too  large  for  the  box 
cars,  should  be  protected  by  tarpaulins. 

381.  The  general  arrangement  of  wheels,   springs,   and 
brakes,  is  the  same  for  the  several  classes  of  cars,  the  chief 
difference  being  in  the  ease  of  springs.     Each  car  rests  upon 
two  "trucks,"  consisting  of  four,  six,  or  eight  wheels,  so 
connected  by  levers  and  springs,  as  best  to  absorb  shocks, 
and  connected  with  the  body  by  a  pin  only,  by  which  the 
passage  of  curves  is  made  quite  easy. 

Cars  used  for  the  movement  of  earth  are  so  arranged  as 
to  allow  the  body  to  be  tipped  up,  that  the  contents  may 
be  quickly  "  dumped,"  either  at  the  sides,  ends,  or  middle, 
as  desired. 

382.  Upon  some  roads,  a  continuous  draw  bar  is  passed 
under  the  whole  train,  the  several  cars  being  attached  to  it, 
and  to  each  other  by  safety  chains  only.     By  adopting  this, 
and  at  the  same  time  by  springing  the  buffer  beams  tight 
upon  each  other,  the  whole  train  becomes  one  piece ;  and 
the  jerks  at  stopping  and  at  starting  are  in  a  great  measure 
avoided. 

As  lightness  combined  with  strength  is  a  desideratum  in 
all  cases,  it  will  be  found  best  to  truss  the  longitudinal 
frame  pieces  of  the  car  with  rods,  rather  than  to  use  large 
and  heavy  beams,  as  done  by  many  builders. 

383.  As  regards  the  mode  of  retarding  trains  of  cars,  the 
practice  of  applying  blocks  to  the  wheels  is  justly  considered 
by  many  as  quite  wrong.     The  brake  should  be  applied  to 
the  rail  and  not  to  the  wheel.     Blocks  drawn  against  the 
wheel  are  supplied  with  friction  by  means  of  levers  worked 

34* 


402  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

by  a  brakeman,  who  can  at  pleasure  cause  the  wheels  to 
slide  upon  the  rail.  A  shoe,  sliding  upon  the  rail,  may  be 
supplied  with  friction  from  the  whole  weight  of  the  car. 
The  retarding  force  should  be  applied  at  once  to  every  car 
alike ;  if  too  much  in  front,  the  rear  cars  are  driven  against 
those  in  advance ;  if  too  much  behind,  the  train  is  liable 
to  break. 

The  proper  place  for  the  brakeman   is  upon  the  top  of 
the  train,  \vhere  all  signals  may  be  quickly  seen. 


CHAPTER    XY 
STATIONS, 


384.  THE  entire  establishment  of  buildings  for  operating 
a  railroad,  consists  of  the 

Terminal,  j  P™!nf r'  j  Stations, 
'(     Freight,    j 

(  Passenger,  )  _ 
Way,  }  }  Stations. 

r'(    Freight,    J 

Engine  houses. 

Repair  shops,  (for  engines). 

Repair  shops,  (for  cars). 

Wood  sheds. 

Water  tanks. 

And  appertaining  to  these,  scales  for  the  weighing  of  cars 
and  freight;  turntables,  transfer  tables,  switch  and  gate 
houses. 

385.  The  location  of  the   several   buildings   mentioned 
above  will  depend  upon  the  situation  of  the  terminus,  the 
character  of  the  traffic,  and  the  number  of  trains  arriving 
and  departing. 

386.  The  passenger  house  should  be  at  the  most  con 
venient  point  of  access  to  the  persons  using  it.     The  freight 


404  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

buildings  should  be  at  the  most  convenient  point  for  receiv 
ing,  shipping,  and  distributing  merchandise. 

The  engine  and  car  houses,  with  the  shops  for  repair, 
may  be  placed  where  the  land  is  cheap,  and  so  distant  from 
dwelling-houses  as  not  to  cause  inconvenience  to  the  in 
mates  thereof  by  smoke  and  noise.  The  wood  sheds,  tanks, 
turntables,  etc.,  etc.,  are  generally  at  the  engine  houses  ; 
weigh  scales,  etc.,  at  the  freight  buildings. 

387.  A  railroad  which  connects  the  interior  with  a  sea 
port,  would  probably  bring  two  classes  of  freight ;  one  for 
export  and  one  for  home  consumption.  The  first  should 
be  carried  at  once  to  the  wharves  and  loaded  into  the  ships 
with  one  transshipment;  while  the  second  should  be  de 
livered  as  near  as  possible  to  the  centre  of  home  trade. 

The  departments  of  arrival  and  departure  should  be  kept 
quite  distinct,  when  the  amount  of  business  transacted  is 
considerable  ;  otherwise  operating  will  become  complicated. 
The  arrival  part  of  a  large  passenger  house  requires  a  great 
number  of  doors,  that  exit  may  be  easy  to  the  large  number 
of  passengers  that  arrive  at  once.  The  departure  rooms 
require  few  doors,  as  departing  passengers  come  singly  or 
in  small  bodies.  Thus,  in  large  cities  the  front  of  a  long 
rectangle  is  given  to  departure,  while  a  long  side,  com 
municating  with  an  outside  platform,  forms  the  arriving 
room. 

One  thing  in  particular  ought  to  be  looked  to  by  Ameri 
can  railroad  companies,  —  the  arrangement  of  public 
vehicles  that  shall  secure  travellers  from  the  impositions 
and  extortions  of  hack-drivers.  No  person  whatever  should 
have  access  to  any  building  except  passengers  and  the  rail 
road  officials.  The  places  of  the  several  carriages,  and  the 
rates  of  pay  for  the  same,  should  be  fixed  by  the  company ; 
the  fare  being  paid  by  checks  bought  by  the  traveller  from 
a  company  agent  at  the  station. 


STATIONS.  405 

388.  The  terminal  freight  house  should  contain  all  of  the 
apparatus  necessary  for  receiving  and  embarking  freight. 
When  the  central  part  of  the  building  is  occupied  by  tracks, 
and  the  sides  by  platforms,  the  landing  platform  should  in 
cline  gently  from  the  car  to  the  door  ;  and  that  for  loading, 
from  the  door  to  the  car.  This  arrangement  facilitates  the 
handling  of  freight.  The  interior  of  the  building  may  be 
divided  into  departments,  either  according  to  the  destination 
or  the  class  of  the  freight. 

«389.  A  terminal  engine  house,  with  a  table  in  the  centre, 
to  contain 

10  engines,  must  be  145  feet  in  diameter. 

15  "  "  150  "  « 

20  «  «  167  "  " 

25  "  "  183  "  " 

30  "  "  200  "  " 

35  "  "  217  "  " 

40  «  a  233  "  " 

45  "  "  250  "  " 

50  "  "  267  "  " 

The  diameter  of  the  table  being  forty-five  feet,  and  the 
engine  occupying,  when  off  from  the  table,  fifty  feet.  Again, 
thirty-two  engines  would  require  a  diameter  of 

32  V  10 

-  +  (2X50)  =  207  nearly. 


The  engines  within  the  house  may  be  supplied  with 
water  from  small  tanks  between  each  alternate  pair  of  pits, 
(each  tank  holding  five  thousand  gallons,)  or  the  entire 
building  may  be  furnished  from  a  cast-iron  pipe  running 
around  the  whole,  and  being  in  connection  with  a  large 
tank.  In  such  pipe  there  should  be  a  gate  over  the  centre 
of  each  pit,  and  near  its  upper  end.  It  may  be  convenient 


406  HANDBOOK   OP   RAILROAD    CONSTRUCTION. 

to  connect  all  to  a  series  of  small  tanks,  by  a  pipe,  that  the 
water  level  may  be  kept  nearly  constant. 

Repair  shops  for  engines  and  for  cars,  may  be  plain,  rec 
tangular  buildings,  so  arranged  as  to  accommodate  the 
necessary  machinery. 

Turntables  consist  of  simply  a  circular  framework  of 
wood  or  iron,  placed  at  the  centre  upon  a  solid  iron  pintle 
which  bears  the  whole  weight,  and  guided  at  the  circum 
ference  by  a  series  of  fifteen,  eighteen,  or  twenty  wheels 
fourteen  or  fifteen  inches  in  diameter.  The  wheels  are 
placed  in  an  independent  spider  frame,  and  run  upon  a 
curved  rail  placed  on  the  bottom  masonry,  and  the  table 
runs  upon  the  top  of  the  wheels,  so  that  the  motion  of  the 
circumference  of  the  table  is  double  that  of  the  wheels. 

The  frame  consists,  first,  of  a  pair  of  timbers  ten  or 
twelve  inches  wide  and  fifteen  or  sixteen  inches  deep,  upon 
which  the  rails  are  placed,  strongly  trussed  so  as  to  throw 
the  load  upon  the  centre.  At  right  angles  to  these  are 
placed,  at  a  distance  of  eight  or  ten  feet,  timbers  5  X  10, 
also  trussed,  which  serve  to  connect  the  load  more  com 
pletely  with  the  wheels.  The  whole  is  stiffened  by  diagonal 
bracing,  and  is  strongly  floored.  The  table  is  turned  by  a 
pinion  upon  itself,  working  into  a  rack  fastened  to  the 
foundation  or  to  the  side  masonry.  The  trusses,  as  also  the 
centre  bearing,  should  be  capable  of  adjustment  vertically. 

The  cost  of  the  table,  exclusive  of  masonry,  is  from 
$1,200  to  $1,800. 

Weigh  scales  are  made  similar  to,  but  stronger  than,  the 
ordinary  hay-scales,  being  rigid  and  strong  enough  to  bear 
the  weight  of  a  locomotive.  Every  car  (freight)  placed 
upon  the  road  should  have  the  number  and  the  exact 
weight  painted  upon  it  in  some  conspicuous  place,  so  that 
the  contained  load  may,  at  any  time,  be  found  by  placing 
the  car  upon  the  scale. 


STATIONS.  407 

At  ivay  stations  the  freight  and  passenger  houses,  wood 
and  water  station,  may  all  be  combined ;  the  plan  and  size 
depending  upon  the  location  and  importance  of  the  station. 
The  relative  position  of  the  tank,  wood  shed,  and  passenger 
house  should  be  such  that  when  the  tender  is  at  the  proper 
place  for  receiving  its  supplies  the  centre  of  a  passenger 
train  of  ordinary  length  shall  be  at  the  passenger  door. 

OF    THE    WATER    SUPPLY. 

390.  The  number  of  engines  leaving  the  terminus  of  a 
road  determines  the  amount  of  water  necessary  at  the  prin 
cipal  stations  ;  and  the  character  of  the  road  and  of  the 
traffic  fixes  the  location  and  size  of  the  way  water  stations. 
The  amount  of  traffic  being  pretty  equally  distributed  over 
the  length  of  the  road,  the  tanks  should  be  placed  at  equal 
equated  distances ;  thus  the  engines  will  need  to  water  at 
closer  points  upon  steep  grades  than  upon  level  roads. 
Generally,  however,  the  water  is  taken  where  it  can  be  got. 
the  location  of  streams  and  springs  fixing  the  place.  Steam, 
hydraulic,  wind,  human,  or  animal  power  may  be  employed 
to  raise  the  wrater  to  the  tank.  Oftentimes  high  springs 
will  fill  the  tanks  without  the  application  of  artificial  power. 
As  we  find  the  liquid  water  in  nature  it  is  more  or  less  im 
pregnated  with  vegetable,  gaseous,  and  saline  matter,  which 
often  impairs  its  fitness  for  mechanical  purposes.  These 
admixtures  are  derived  from  the  rocks  and  ground  over  or 
through  which  the  water  flows.  The  incrustations  which 
form  in  boilers  are  caused  by  the  precipitation  of  the  im 
purities  in  consequence  of  the  concentration  of  water  in  the 
boiler.  They  may  be  effectually  removed,  no  matter  what 
their  nature,  by  boiling  charcoal  in  the  water.  If  the  water, 
previous  to  filtration,  can  be  heated,  to  expel  all  the  air  and 
carbonic  acid  gas,  which  is  often  the  solvent  of  the  foreign 


408 


HANDBOOK   OF   RAILROAD   CONSTRUCTION. 


matter,  the  filtering  process  will  be  accelerated,  and  will  be 
more  effectual.  Rain  water  is  more  pure  than  any  other ; 
practically,  perfectly  so.  River  water  comes  next  to  it. 
Spring  water  is  generally  adulterated  with  basic  salts  in 
various  forms,  most  of  which  may  be  precipitated  by  gently 
heating  and  filtering  through  charcoal. 

391.    Fig.  157  shows  a  convenient  form  for  a  tank  house, 
with  pump  and  heater. 


Fig.  157. 


A  shows  half  in 
terior  section  of  the 
tank. 

B,  half   elevation 
of  tank. 

C,  pump  ;  C',  sup 
ply  pipe  ;   d,  suction 
pipe  and  strainer. 

E,  heater. 

e,  the  short,  and  A, 
the  long  pipe. 

H,  the  discharge 
pipe. 

G,  discharge 
valve. 

I,  counter  weight 
for  discharge  pipe. 

K,  wheel  for 
weight  rope. 

L,  scale  showing 
amount  of  water  in 
the  tank. 


The  heater  shown  in  the  cut  is  made  of  a  coil  of  two 
inch  pipe  of  iron.  The  short  pipe  descends  from  within  six 
inches  of  the  bottom  of  the  tank  to  within  two  or  three  feet 
of  the  floor ;  then  bending  four  or  five  times  around  spirally, 


STATIONS.  409 

turns  up  through  the  centre  of  the  coil,  and  runs  three  or 
four  feet  into  the  tank.  A  small  grate  is  placed  in  the 
lower  part  of  the  coil,  and  the  whole  apparatus  is  cased  in 
sheet  iron.  By  such  an  arrangement  of  pipe,  circulation  is 
obtained,  and  the  water  in  the  tank  is  kept  quite  warm. 
The  following  rules  and  tables  may  be  found  convenient. 

392.  The  velocity  of  water  in  any  pipe  necessary  to  dis 
charge  a  given  quantity,  in  a  fixed  time,  is  expressed  by 

144(7 
a 

Where  C  is  the  number  of  cubic  feet  per  hour,  and  a  the 
area  of  the  pipe. 

393.  The  head  necessary  to  send  water  through  a  given 
length  of  pipe,  of  any  diameter,  is  shown  by  the  formula 


D+C'  —  ' 

Where  C=  a  constant. 

C'  =  constant  for  diameter  of  pipe. 
D  =  diameter  of  pipe. 
ff=  heads  required. 

The  experimental  values  of  C  and  C'  are  as  follows :  Let 
V  equal  the  velocity  in  feet  per  minute,  and  we  have 

v.  c. 

60  8.62 

70  11.40 

80  14.58 

90  17.95 

100  ,  21.56 

120  29.70 

140  38.90 

150  44.00 

180  62.13 
35 


410  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Also,  the  values  of  Cf  are 

Diameter  of  pipe.  C'. 

2  .000 

3  .006 

4  .028 

5  .053 

6  .078 

7  .104 

8  .134 


EXAMPLE    OF   USE    OF   PRECEDING    RULES. 

Required  the  head  of  water  necessary  to  send  1,333  cubic 
feet  of  water,  or  10,000  gallons  per  hour,  through  an  eight 
inch  pipe  one  thousand  feet  long. 

The  velocity  by  rule  one  will  be 

Q2  -Q_.     =  3840  feet  per  hour,  or  64  feet  per  minute. 
O     .<oO'± 


By  rule  two  (the  value  of  C  for  60  being  8.62,  and  for  70 
11.40,  that  for  64  is  10  nearly),  we  have 

10       =1.23, 


8  +  0.134 

which  multiplied  by  ten  (the  number  of  times  that  one  hun 
dred  is  contained  in  one  thousand  feet,  the  distance),  gives 
the  result,  twelve  inches  or  one  foot,  which  is  the  required 
head;  and  if  the  entrance  to  the  tank  is  twenty  feet  high, 
we  have,  as  the  necessary  head,  20  + 1  =  21  feet. 

394.   The  formula  expressing  the  power  of  an  engine  to 
raise  a  given  amount  of  water  is 

WV 


33000 ' 


STATIONS.  411 

Where  W  is  the  weight  of  a  column  of  water,  and  Vthe 
velocity  in  feet  per  minute  ;  also  33,000  the  expression  of  a 
horse-power.  For  example,  how  many  horse-power  must 
an  engine  possess  to  raise  one  thousand  cubic  feet  of  water 
per  hour  through  a  six  inch  pipe  fifty  feet  high  ? 
The  velocity  will  be 

1000  X  144 

6* X  0.7854  =  50°° feet Per  hour> 

or  eighty-three  feet  per  minute.     The  weight  of  a  column 
of  water  fifty  feet  high  and  six  inches  in  diameter  is 


Also, 

61 21  X  83 

~~33000~  =  4  horse-power  nearly. 

395.  Among  the  pumps  now  in  use  for  raising  water  at 
railroad  stations  are  Carpenter's  rotary,  Worthington's,  Mc- 
Gowan's,  and  that  of  Messrs.  Perkins  and  Bishop,  either  of 
which  answers  every  purpose. 

396.  TABLE    SHOWING   THE   WEIGHT   AND    COST   PER   FOOT    OP 

CAST-IRON   PIPE. 


Diameter  of 
bore. 
Inches. 

Thickness  of 
metal. 
Inches. 

Weight  of  pipe  per 
lineal  foot. 
Lbs. 

Cost  of  pipe  per 
lineal  foot. 
Cents. 

i 

i 

3.06 

15 

ii 

* 

3.67 

18 

1* 

i 

4.29 

21 

If 

f 

7.81 

39 

2 

f 

8.73 

44 

*i 

§ 

9.65 

48 

H 

i 

14.70 

73 

H 

* 

15.93 

80 

3 

i 

17.15 

86 

412 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


The  weight  of  a  cubic  foot  of  cast-iron  being  450  Ibs., 
and  the  price  being  five  cents  per  Ib. 


TABLE    SHOWING   THE    CAPACITY  OF  MCGOWAN'S    DOUBLE    ACTING 

PUMPS. 


Explanation. 

No.  1. 

No.  2. 

Time  required  to 
fill  a  6600  gallons 
tank. 

Stroke  in  inches, 

5 

H| 

Hours. 

Diameter  of  plunger, 

28 

31 

Area  of  plunger, 

5.278  in. 

7.70  in. 

Ifi 

&*« 

Cube  of  half  stroke  in  gallons, 

0.114 

0.283 

a  §  6 
&  tt 

ay 

|H             At       10 

136.8 

339.6 

49 

19 

.  ji         "20        « 

273.6 

679.2 

24 

10 

1,        "     30       J 

410.4 

1018.8 

16 

7 

oa        •    "      40            S 

547.2 

1358.4 

12 

5 

fl                                                Si 

-2         "50         rL 

684.0 

1698.0 

10 

4 

S)        «     60        8 

820.8 

2037.6 

8 

3JL 

.      G                                    rM 

" 

"     70         2 

957.6 

2377.2 

7 

3 

<s>                            •*•» 

f"     80        ^ 

1094.4 

2716.8 

6 

2^- 

"^ 

0                "         90             & 

1231.2 

3058.4 

5 

2? 

CO 

S      "  100 

1368.0 

3396.0 

5 

2 

CHAPTER  XVI. 


MANAGEMENT. 


All  that  is  required  to  render  the  efforts  of  railroad  companies  in  every  respect 
equal  to  that  of  individuals,  is  a  rigid  system  of  personal  accountability  through 
every  grade  of  service. — D,  C.  McCallum. 


ORGANIZATION  OF  EMPLOYEES. 

397.  RAILROAD   management   may  be  divided  into  two 
grand  departments, — 

Financial  management. 
Operating  management. 

The  first  of  these  does  not  properly  come  into  a  work  of 
the  present  kind.  It  embraces  the  entire  system  of  accounts. 
Its  officers  are  a  president,  secretary,  treasurer,  attorney, 
and  directors. 

398.  The  operating  management  is  subdivided   as   fol 
lows  :  — 

The  mercantile  department. 
The  mechanical  department. 

The  first  embracing  every  thing  relating  to  the  adjusting 
of  tariffs,  the  transport  of  passengers  and  freight,  the  em- 

35* 


414  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

barking  and  delivering  of  goods,  and  the  weighing  and 
measuring,  ticket  and  receiving  offices,  steamboat,  stage, 
and  railroad  connections.  The  second,  the  maintaining  the 
road-bed,  superstructure,  bridging,  masonry,  buildings,  and 
fixed  stock  in  working  order  ;  making  all  repairs,  renewals, 
enlargements,  and  alterations,  and  the  purchase,  inspection, 
maintaining,  and  operating  of  the  rolling  stock.  These  de 
partments  are  again  divided  and  subdivided  until  we  come 
to  the  minutest  details. 

NOTE.  —  That  part  of  Chapter  XVI.  in  italics  is  extracted,  by  permission, 
from  the  elaborate  Report  of  D.  C.  McCallum  to  the  stockholders  of  the  New 
York  and  Erie  Railroad,  (March  25,  1856). 

399.  The  following  general  principles  govern  the  forma 
tion  of  an  efficient  system  of  operations. 

First.    A  proper  division  of  responsibilities. 

Second.  Sufficient  power  conferred  to  enable  the  same  to 
be  fully  carried  out,  that  such  responsibilities  may  be  real  in 
their  character. 

Third.  The  means  of  knowing  whether  such  responsibilities 
are  faithfully  executed. 

Fourth.  Great  promptness  in  the  report  of  all  derelictions 
of  duty,  that  evils  may  at  once  be  corrected. 

Fifth.  Such  information  to  be  obtained  through  a  system  of 
daily  reports  and  checks  that  will  not  embarrass  principal 
officers  nor  lessen  their  influence  with  their  subordinates. 

Sixth.  The  adoption  of  a  system,  as  a  whole,  which  will 
not  only  enable  the  general  superintendent  to  detect  errors 
immediately,  but  will  also  point  out  the  delinquent. 

400.  A  system  of  operations  to  be  efficient  and  successful 
should  be  such  as  to  give  to  the  principal  and  responsible 
head  of  the  running  department  a  complete  daily  history  of 
details  in  all  their  minutice.     Without  such  supervision  the 
procurement  of  a  satisfactory  annual  statement  must  be  re- 


MANAGEMENT. 


415 


garded  as  extremely  problematical.  The  fact  that  dividends 
are  made  without  such  control  does  not  disprove  the  position, 
as  in  many  cases  the  extraordinarily  remunerative  nature  of 
an  enterprise  may  insure  satisfactory  returns  under  the  most 
loose  and  inefficient  management. 

All  subordinates  should  be  accountable  to,  and  directed 
by,  their  immediate  superiors  only.  Each  officer  must  have 
authority,  with  the  approval  of  the  general  superintendent, 
to  appoint  all  persons  for  whose  acts  he  ig  held  responsible, 
and  to  dismiss  any  subordinate  when  in  his  judgment  the 
interests  of  the  company  demand  it. 

401.  The  following  table  shows  the  rate  and  direction  of 
subordination  for  a  first  class  railroad :  — 


f  Section  men. 

'  Superintendent  (  Road-master,   i  Section  men. 
of  Road.         I  Road-master.  1  Section  men. 
[  Section  men. 
Foreman  Machine  shop,  Machinists. 

"        Blacksmith  shop,  Blacksmiths. 
•Superintendent  I          "        Car  shop,  Carpenters, 
of  Machinery,  j          "        Paint  shop,  Painters. 

Engineers  (not  on  trains),  Firemen. 
Car-masters,  Oil  men  and  cleaners. 


General  Superin 
tendent. 


General  passen 
ger  agent. 


General  freight 
agent. 


Supply  agent. 
Fuel  agent. 


Conductors. 
Mail  agents. 

Station  agents.  I 

Express  agents. 
Police. 

Conductors. 
Station  agent. 


Ticket  collectors. 


(  Brakemen. 
Engineers  (on  trains). 


Weighers. 

Gaugers. 

Yard-masters. 

Clerks,  Teamsters  furnishing  supplies. 

All  men  employed  about  the  wood  sheds. 


DUTIES   OF  EMPLOYEES. 


402.  The  General  Superintendent  has  entire  control  of  all 
of  the  heads  of  departments ;  he  issues  his  orders  to  the 
heads  only,  and  is  the  main  agent  for  transferring  the 
resolves  of  the  directors  to  the  operating  department,  and 


416  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

the  channel  through  which  the  reports  of  the  departments 
go  to  the  directory. 

The  Superintendent  of  the  Road  has  complete  charge  of 
the  road-bed,  superstructure,  bridging,  masonry,  and  build 
ings  ;  also  all  removals,  enlargements,  and  alterations.  He 
should  be  a  thorough  civil  engineer,  able  in  every  respect  to 
build  a  railroad  from  beginning  to  end. 

The  Superintendent  of  Machinery  has  charge  of  the  pur 
chase,  inspection,  repair,  and  operating  of  all  of  the  rolling 
and  fixed  machinery,  of  shops,  engine  houses,  turntables, 
tanks,  and  weigh  scales.  He  is  responsible  for  the  good 
condition,  proper  adaptation  and  efficiency  of  the  entire 
equipment  of  engines  and  cars. 

The  General  Passenger  Agent  fixes,  under  the  direction 
of  the  president  and  general  superintendent,  the  prices  of 
passenger  transportation,  has  charge  of  all  conductors, 
ticket  sellers,  station  police,  mail  and  express  agents,  of 
stage,  steamboat,  and  railroad  connections,  and  of  all  opera 
tions  incident  to  transporting  passengers. 

The  General  Freight  Agent  has  charge  of  all  persons 
occupied  at  all  of  the  stations  in  forwarding  and  receiving 
merchandise,  in  measuring  and  weighing,  in  receiving 
money,  and  bookkeeping,  station  agents,  and  train  hands. 
He  makes  and  regulates,  with  the  approval  of  the  president 
and  general  superintendent,  the  tariff  for  freights ;  contracts 
with  connecting  roads,  and  insures  the  benefits  of  such 
agreements,  examines  all  claims  for  damages  to  freight,  and 
sees  that  such  are  properly  settled. 

The  Agent  for  Wood  contracts,  with  the  approval  of  the 
general  superintendent,  for  the  supply  of  the  necessary 
amount  of  fuel ;  attends  the  measurement,  inspection,  and 
delivery  at  the  proper  places;  registers  each  month  the 
amount  of  fuel  supplied  and  used,  and  the  location  and 
amount  on  hand. 


MANAGEMENT.  417 

The  Supply  Agent  has  charge  of  the  supply  of  all  ma 
terials  in  use  in  all  departments ;  iron,  timber,  engines,  rails, 
bridges,  and  every  thing  in  use  upon  the  road;  charging 
each  department  with  its  correct  quantity  and  quality  of 
material  received. 

Road-masters  will  have  charge,  under  the  superintendent 
of  the  road,  of  the  maintenance  of  the  road-bed  and  super 
structure  of  divisions  of  from  twenty-five  to  fifty  miles  in 
length,  depending  upon  the  care  that  the  road-way  may 
need.  They  will  have  charge  of  gravel  trains,  and  of  wood 
trains,  which  run  under  the  orders  of  the  superintendent  of 
the  road.  They  should  pass  over  their  divisions  at  least 
once  per  day.  Under  them  are  placed  section  men,  having 
care  of  ten  miles  each,  being  supplied  with  the  proper  tools 
and  signals.  They  must  pass  over  their  respective  sections 
at  least  once  per  day  in  a  hand  car.  They  should  see  that 
every  switch,  frog,  chair,  and  rail  on  their  section  is  in 
proper  order,  and  report  at  once  any  defects,  which  cannot 
be  remedied  by  them,  in  the  track,  to  the  road-master. 

Engineers  are  subject  to  the  superintendent  of  machinery 
when  off',  and  to  the  conductor  when  on,  the  trains.  None 
but  a  man  well  acquainted  with  the  details  of  machinery, 
and  who  has  served  in  a  locomotive  machine  shop,  and  is 
in  every  respect  temperate  and  steady,  should  fill  this  berth. 
•  Foremen  of  the  blacksmith,  machine,  carpenter,  and  car 
shops,  are  subject  to  the  superintendent  of  machinery,  and 
have  charge  of  the  repairs  and  cleaning  of  the  engines,  cars, 
and  other  machinery. 

Car-masters  have  charge  of  the  men  employed  in  clean 
ing,  oiling,  and  examining  the  cars  and  their  wheels.  The 
cars  should  be  thoroughly  examined  at  the  end  of  each  trip, 
and  at  each  stop,  by  an  inspector  who  accompanies  the 
train  and  looks  to  the  wheels,  axles,  boxes,  and  brakes. 


418  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Conductors.  —  A  conductor  of  a  train  should  be  a  ma 
chinist,  a  prompt,  active  man,  who  should  station  himself 
on  the  top  of  the  cars  in  such  a  position  as  to  see  the  whole 
train,  and  able  at  any  moment  to  communicate  with  the 
engineer.  He  should  direct  the  running  of  the  train,  and 
control  the  engineer  and  the  person  who  takes  the  fares. 
The  latter  should  confine  himself  to  the  inside  of  the  cars. 


NUMBER  OF  TRAINS  TO  BE  USED. 

403.  This  is  determined  by  the  quantity  and  quality  of 
the  material  to  be  transported,  and  by  the  character  of  the 
road.  The  train  should  not  be  so  heavy  as  to  be  beyond 
the  power  of  the  engines  upon  the  steepest  grades,  nor  so 
light  as  to  increase  unnecessarily  the  number.  A  road 
doing  a  large  passenger  business  must  accommodate  the 
public  as  far  as  possible  as  regards  the  time  of  departure 
and  arrival,  and  the  connections  with  other  roads.  A  freight 
road  must  regard  more  the  character  of  the  road.  Some 
classes  of  freight  (ice,  beef,  etc.)  do  not  admit  of  delay.  As 
we  increase  the  number  of  trains,  the  ratio  of  time  em 
ployed  in  actual  work  to  the  whole  train  under  steam  is  de 
creased,  as  there  must  be  much  time  lost  on  sidings  in  wait 
ing  for  trains  to  pass.  Liability  to  accidents  is  also  incurred. 
Commercial  circumstances,  more  than  any  other,  will  de 
termine  the  proper  number  and  class  of  trains. 


AMOUNT  OF  SERVICE  OF  ENGINES. 

404.  This  is  much  less  than  is  generally  supposed.  The 
number  of  engines  required  to  perform  any  amount  of  work 
is  considerably  greater  than  the  number  actually  in  motion, 


MANAGEMENT.  419 

because  of  liability  to  accident,  time  required  for  cleaning 
and  repair.  The  New  York  State  Engineer's  Report  for 
1854  gives,  as  the  number  of  engines  on  2,500  miles,  668,  or 
one  engine  per  3|  miles.  Also,  668  engines  run  per  annum 
11,393,000  miles,  or  17,055  miles  per  annum  per  engine  ; 
thus  requiring  .00005863  of  an  engine  per  mile  run  per 
annum. 

This  is  very  nearly  fifty-five  miles  per  day,  (313  days  per 
annum).  Also,  £/fo  giyes  yVs  °f  an  engine  per  mile  of  road, 
and  the  same  report  gives  the  following  :  — 

One  locomotive  for  3J  miles  of  road. 
One  passenger  car  for  2^  miles  of  road. 
One  freight  car  for  ^fly  miles  of  road. 


Or  each  mile  needs 


of  a  locomotive. 
of  a  passenger  car. 
3  freight  cars. 


Or  to  one  engine  7^  passenger  cars,  and  10T7^  freight  cars. 
From  Lardner's  Railway  Economy  it  appears  that  the 
average  daily  run  of  an  engine  is  forty-two  miles,  or  seventy- 
five  miles  per  day,  working  four  days  in  the  week.  That 
the  daily  service  is  two  hours  working,  and  three  and  three 
quarters  hours  standing  with  steam  up.  The  maximum 
annual  mileage  mentioned  by  Lardner  is  that  upon  the 
Belgium  lines,  and  was  21,737.  The  maximum  in  America 
has  been,  as  far  as  we  have  been  able  to  ascertain,  22,000, 
and  this  for  eighteen  years. 

NOTE  1.  —  Two  little  eight  ton,  four  wheeled,  Stephenson  engines,  cylinders 
10  X  16,  four  and  a  half  feet  drivers,  inside  connection,  copper  fire-boxes,  have 
averaged  22,000  miles  per  annum,  with  trains  weighing  forty  tons  exclusive  of 
engine  and  tender,  for  eighteen  years,  costing  about  $700  per  annum  each  for 
repairs,  or  $3.18  cents  per  mile  run,  upon  the  Bangor  and  Oldtown  Railroad 
(Maine). 


420  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

NOTE  2.  —  In  the  Report  of  the  Railroad  Commissioners  of  the  State  of  Ne\r 
York  for  the  year  ending  September  30,  1855,  is  the  following  :  — 

One  engine  is  required  for  each  three  and  a  half  miles  ;  or  one  engine  in  con 
stant  use  for  five  and  a  quarter  miles.  The  average  run  per  annum  by  each 
engine  in  actual  use  is  22,823  miles;  or  16,302  to  all  of  the  engines.  Also,  as 
regards  the  work  done  by  cars. 

Effective  in  Miles  per  Distance  run  per 

constant  use.  car.  annum  per  car. 

650  4  45.126 

246  11 

Freight,  7500  0.35  11.970- 

the  number  of  miles  being  2,615. 


EXPENSES,  RECEIPTS,  PROFITS. 

EXPENSES. 

405.  American  railroad  reports  as  a  general  thing  do  not 
analyze  the  cost  of  working.  The  gross  expense  is  given, 
and  in  some  cases  is  primarily  divided.  Besides  Ihe  retro 
spective  use  of  a  minute  division  of  expenses,  which  enables 
us  to  see  what  system  is  the  mosj;  economical,  there  is  a 
prospective  use,  namely,  the  formation  of  estimates  for 
future  operations  and  a  correct  base  for  establishing  tariffs. 
If  the  circumstances  of  the  traffic  remain  the  same,  an  esti 
mate  of  what  the  cost  will  be  at  any  time  is  easy ;  but  if 
they  change,  the  data  for  the  estimate  change  also.  That 
we  may  at  all  times  possess  these  data,  we  should  know 
every  year  just  the  cost  of  working  each  article  of  traffic. 
It  is  not  enough  that  the  gross  receipt  exceeds  the  whole 
expense ;  even  then  the  road  may  be  working  unprofitably. 
Unless  each  item  of  transport  pays  for  itself,  we  are  taxing 
unjustly  some  other  item,  (except,  indeed,  in  such  cases  as 
adopting  low  rates  in  order  to  fill  trains  running  in  one 
direction  which  would  otherwise  run  empty).  An  analysis 
of  cost  will  also  show  whether  or  not  it  is  best  to  attract 
an  increased  amount  of  business  by  a  reduction  of  rates. 


MANAGEMENT. 


421 


406.  The  whole  cost  of  operating  and  of  maintaining  a 
railroad  may  be  generally  and  specially  divided  as  fol 
lows  :  — 


(A)  Interest  on  construction  and  equipment  capital. 


Cost  of  Road-bed. 
"      Superstructure. 


(B)  Maintenance  of  way  and  works. 


Road-bed. 
Buildings. 
Superstructure. 


(C)  Maintenance  of 
the  fixed  and 
rolling  stock. 


Locomotives. 


Cars. 


F  i  x  e  d  m  a  - 
chinery. 

J 


Passenger. 


Freight. 


Passenger. 


Cars. 
Fixed  machinery. 

Material. 

Labor. 

Material. 

Labor. 

Material. 

Labor. 

(Fuel,    oil,  and 
•<      waste. 
(  Salaries. 

J  Material. 
Labor. 

(  Fuel,    oil,  and 
<      waste. 
(  Salaries.    * 


Working. 
Maintaining. 
Working. 
Maintaining. 

Working. 


(  W  a  r  m  i  n  g  , 


Freight. 

{In  shops. 
On  road. 


( 


(D)  Salaries  of  hands  employed  in 
and  about  trains. 


(E)  Station  expenses. 


j  Passenger, 
1  Freight. 


(F)  General  superintendence. 


[  Oil  and  waste. 
Maintaining.    {  M,aa*^ial  and 

I  Oil  and  waste. 
<  Material  and 
(  labor. 

(  Machinery.      (  Oil  and  waste. 

<(  T  a  n  k  s  and  t  Materials  and 
tables.  (  labor. 

Conductors. 

Ticket  sellers. 

Clerks. 

Brakemen. 

Porters. 

Conductors. 

Station  agents. 

Brakemen. 

Weighers  and  guagers. 
Warming  and  lighting. 
Police. 

Warming  and  lighting. 
Police. 

Salaries. 

Travelling  expenses. 
Office  expenses. 
Stationery. 
Advertising,  &c.,  &c. 


Passenger. 


Freight. 


The  actual  general  decision  of  the  operating  expenses 


422  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

upon  the  New  York   State  system  of  roads  was,  for  1854, 
as  follows.     (See  State  Engineer's  Report). 

Way  and  works,  1,123  dollars  per  mile  of  road. 

Machinery,  2,072 

Salaries  on  and  about  trains,    640        " 
Stations,  30        "  " 

General  superintendence,          333        "  " 

Total,  4,198       " 

That  the  detailed  expenses  may  be  charged  to  the  proper 
departments,  and  that  we  may  be  able  to  take  out  the  exact 
cost  of  working  any  one  class  of  trains,  or  of  carrying  any 
article  of  transport,  the  following  form  should  be  filled. 


MANAGEMENT. 


423 


3 


S  o 


no 


PUT?  no 


.•s  "3 

Si 

I  -2 


pq 


0         -< 


S   1 


424 


HANDBOOK    OF   RAILROAD    CONSTRUCTION. 


o  2' 

IV 

11 
11- 


Station 
expenses. 


. 

1  i 


FIXED 
MACHINE 


os 


•-i  tO 

co  <N 


—    -N 

*+  t^ 

00  O 


s  s 


vn       co 


MANAGEMENT.  425 

408.  The  following  general  measures  are  recommended 
by  Lardner  in  his  Railway  Economy,  as  being  the  means  of 
obtaining  increased  economy  in  the  working  of  railroads. 

1st  So  to  manage  the  traffic  as  to  cause  the  cars  to 
carry  more  complete  loads. 

2d.    To  encourage  the  transport  to  long  distances. 

3d.  To  regulate  the  tariff  so  as  to  give  the  largest  possi 
ble  number  of  cars  to  each  engine. 

4th.  To  adjust  the  tariffs  where  the  business  is  chiefly  in 
one  direction,  so  as  to  attract  return  traffic,  that  the  cars 
may  not  run  without  a  load. 

5th.  Not  to  increase  the  number  of  trains  beyond  a  rea 
sonable  accommodation  of  traffic. 

6th.  To  diminish  as  far  as  possible  express  trains,  if  it  be 
not  practicable  to  abolish  them  altogether. 


RECEIPTS    AND    PROFITS. 

409.  The  distribution  of  expenses,  as  we  have  seen,  is 
somewhat  complicated,  and  is  systematically  done  upon  a 
very  few  roads.  The  classification  of  receipts  is,  however, 
very  easy,  and  is  properly  detailed  in  nearly  all  railroad 
reports.  Upon  the  New  York  State  railroads,  the  following 
was  the  division  for  the  year  1854. 

Average  receipts  per  mile  of  road, 

Passengers, $4,074.16 

Freight, •  3,776.72 

Extras, 427.28 

Whole,        .'     ":     '".  ;~'.       l.1       I         .  $8,278.16 

Whole  expense, $4,710.14 

or  fifty-seven  per  cent,  of  the  receipts. 

36* 


426  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Receipts  per  mile  run  by  trains, 

Passengers,    .         .         '.         .         .         .         .  $1.32 

Freight,              .         .         .         .       " .         .         .  2.02 

Extras,            .         .         .         .         .         .      '   .  1.67 

Whole, $5.01 

Average, 1.67 


Whole  expense  per  mile  run  by  train,          .         .      $0.97 
Average  receipts  per  passenger  and  per  ton,  per  mile, 

Passenger,        .         .         .  .  .         1.95  cents, 

Ton, .     2.79     « 

Average  of  passenger  or  ton,     .         .  .         2.37     " 
Average  expense  of  passenger  or  ton,   .         .     1.38     " 

410.  Upon  the  New  York  and  Erie  Railroad  for  the  year 
ending  September  30,  1856. 

Receipts  per  mile  of  road, 

Passengers, $3,397.34 

Freight, 7,143.42 

Express  and  mail, 397.84 

Whole, $10,938.60 

Whole  expense  per  mile  of  road,      .         .  5,263.00 

or  forty-eight  per  cent  of  the  receipts. 
Receipts  per  mile  run  by  trains, 

Passengers, $1.16 

Freight, .         .        2.13 

Average  receipts  per  passenger  and  per  ton,  per  mile, 

Passenger, 2.02  cents, 

Ton, 2.37    " 

411.  Upon  the  New  York  State  roads, 


MANAGEMENT,  427 

Average  number  of  passengers  per  mile  run,           .    ,     .  57.4 

Average  distance  travelled  by  passengers,           .         .  ,  .        81.4 

Average  tons  per  mile  run,    .         .                   .         .         .  90.0 

Average  distance,  whole  number  of  tons  carried,         .  .      177.0 
Length,         .         .         .         .  ..'*..       .              496  miles, 

Freight  tonnage,       .         .         .     ,    .    150,673,997  « 

Passenger,  .         .        ..    ;     .         •   '        84,069,398  " 

412.  It  is  of  course  an  object  on  every  railroad  to  make 
the  gross  receipts  overbalance  the  gross  expense  by  the 
largest  possible  amount.  The  elements  which  determine 
the  gross  receipts  are, 

The  charge  per  mile,  for  transport, 
The  number  of  units  transported, 
The  distance  carried, 

of  which  the  company's  directors  can  control  the  first  only, 
except  as  adjustment  of  rates  may  attract  business. 

Reduction  of  tariff,  to  a  certain  degree,  has  the  effect  of 
increasing  the  receipts  by  augmenting  the  number  of  fares ; 
but  the  reduction  may  be  carried  too  far.  So,  also,  for  a 
certain  distance,  increased  rates  will  increase  the  whole 
receipts  ;  but  in  this  case,  also,  the  extreme  must  be  avoided. 
The  point  to  be  arrived  at  is,  evidently,  that  at  which  the 
difference  of  expense  and  receipt  is  the  greatest,  and  this  is 
not  necessarily  when  receipts  are  the  greatest. 

We  can  make  the  receipts  nothing  either  by  making  the 
charges  so  large  that  nothing  can  bear  them,  or  so  small  as 
to  vanish.  Even  when  the  receipts  are  0,  we  still  have  the 
expense  of  moving  the  empties. 

By  forming  a  table  in  which  one  column  shall  show  the 
different  charges,  and  the  second  the  corresponding  amounts 
transferred,  with  the  consequent  receipts  and  cost  of  work 
ing,  which  shall  find  which  rate  of  charge  will  give  the 
greatest  difference  between  expense  and  receipt. 


428  HANDBOOK   OF   RAILROAD   CONSTRUCTION. 


EXPRESS   TRAINS. 

413.  Express  trains  are  a  source  of  vast  expense,  di 
rectly  and  indirectly,  which  can  never  be  repaid  by  any 
practicable  tariff  to  be  levied  upon  them. 

Dr.  Lardner,  (1850):  —  Resolved,  That  this  meeting 
recommend  the  adoption  of  a  higher  rate  of  fare  upon  ex 
press  passenger  trains,  corresponding  in  some  degree  to 
the  increased  cost  of  such  trains.  —  American  Railroad  Con 
vention  of  1854. 

INCREASED    COST    OF   WORKING. 

This  is  due  to  the  extra  wear  and  tear  of  engines,  cars, 
and  road,  from  increased  speed,  and  also  to  the  delays 
occasioned  to  other  trains  in  motion  at  the  same  time. 

The  influence  of  express  trains  is  felt  not  only  by  them 
selves,  but  by  nearly  all  the  trains  upon  the  road. 

NOTE.  —  To  determine  the  most  economical  speed,  regard  need  only  be  had 
to  the  variable  elements  of  cost,  namely :  cost  of  power,  and  maintenance  of 
superstructure,  and  rolling  stock ;  assuming  the  power  expended  as  the  resist 
ance,  and  the  cost  of  repairs  of  machinery  and  superstructure  as  the  velocity,  we 
form  the  following  table  :  — 


Velocity  in 
miles  per 
hour. 

Resistance 
in  pounds 
per  ton. 

Hours  con. 
in  going 
300  miles. 

Product  of  col 
umn  2x8. 

Cost  of 
repairs. 

Result. 

10 

8.6 

30 

258 

100 

358 

15 

9.3 

20 

186 

150 

336 

20 

10.3 

15 

154 

200 

354 

25 

11.6 

12 

139 

250 

389 

30 

13.3 

10 

133 

300 

433 

35 

15.2 

8.60 

131 

350 

481 

40 

17.3 

7.50 

130 

400 

530 

45 

19.8 

6.67 

132 

50 

22.6 

6 

136 

60 

29.1 

5 

145 

100 

66.5 

3 

200 

MANAGEMENT.  429 

The  result  is-found  by  adding  the  product  of  columns  2  and  3,  or  column  4  to 
column  5,  from  which  the  minimum  cost  is  seen  to  be  produced  by  a  very  little 
more  than  fifteen  miles  per  hour'.  The  variable  (and  above  assumed)  element  is 
the  rate  of  increase  of  cost  of  maintenance. 

All  trains  in  motion  at  the  same  time  within  a  certain 
distance  of  the  express,  must  be  kept  waiting  with  steam 
up,  or  be  driven  with  extra  velocities  in  order  to  keep  out  of 
the  way. 

Where  the  time  table  is  so  arranged  as  to  call  for  speed 
nearly  equal  to  the  full  capacity  of  the  engine,  it  is  very  obvi 
ous  that  the  risks  of  failure  in  "  making  time  "  must  be  much 
greater  than  at  reduced  rates ;  and  when  they  do  occur,  the 
efforts  made  to  gain  time  must  be  correspondingly  greater 
and  uncertain.  A  single  example  will  be  sufficient  to  show 
this :  — 

A  train  whose  prescribed  rate  of  speed  is  thirty  miles  an 
hour,  having  lost  five  minutes  of  time,  and  being  required  to 
gain  it,  in  order  to  meet  and  pass  an  opposing  train  at  a  sta 
tion  ten  miles  distant,  must  necessarily  increase  its  speed  to 
forty  miles  an  hour ;  and  a  train  whose  prescribed  rate  of 
speed  is  forty  miles  an  hour,  under  similar  circumstances, 
must  increase  its  speed  to  sixty  miles  an  hour ;  in  the  former 
case  it  would  probably  be  accomplished,  whilst  in  the  latter  it 
would  more  probably  result  in  failure ;  or,  if  successful,  it 
would  be  so  at  a  fearful  risk  of  accident. 

But  a  failure  in  either  case  would  have  the  effect  of  retard 
ing  the  movement  of  the  opposing  train,  deranging  the  time 
of  those  of  the  same  and  of  an  inferior  class  in  both  directions, 
involving,  perhaps,  on  the  part  of  the  latter,  the  necessity  of 
similar  struggles  for  time,  and  thus  may  prove  the  primary 
cause  of  accident  to  all  trains  whose  movements  may  have 
been  affected  thereby. 

The  first  cost  of  locomotives,  (assuming  the  cost  to  in- 


430  HANDBOOK   OF   KAILROAD    CONSTRUCTION. 

crease  with  the  weight,)  is  thirty  per  cent,  greater  for  express 
trains,  than  for  those  of  the  second  or  third  class. 

The  cost  of  repairs  being  assumed  as  the  product  of  the 
weight  by  distance  run,  and  this  distance  being  the  same, 
is  as  the  weight,  or  increased  thirty  per  cent.  (This  as 
sumes  the  power  to  be  equally  well  adapted.) 

The  cost  of  cars  does  not  (though  it  ought),  differ  much 
for  express  or  slow  trains ;  the  cost  of  repairs  will  certainly 
be  increased. 

The  interest  of  construction  capital  to  be  charged  to 
expresses,  will  be,  their  mileage  proportion  plus  any  expense 
which  may  have  been  incurred  in  reducing  curves  and 
grades ;  the  proportion  of  repairs  of  superstructure,  charged 
to  expresses,  will  depend  on  their  weight.  The  locomotive 
causes  f  f  of  the  wear  of  rails,  and  as  the  weight  of  the  en 
gines  is  increased  thirty  per  cent,  the  increased  wear  will 

beH- 

The  use  of  stations  and  of  employees  costs  no  more  for 
express  than  for  accommodation  trains. 

The  repairs  of  locomotives  will  be  nearly,  if  not  quite,  as 
the  product  of  their  weight  by  the  distance  run ;  and  this, 
from  the  above,  will  be  thirty  per  cent,  greater  on  an  express 
than  on  an  ordinary  train,  the  distance  being  the  same. 

The  carriages  for  express  trains  ought  to  be  at  once 
stronger  and  more  convenient  than  those  for  the  slower 
work,  the  shocks  arising  from  irregularities  in  the  rails  being 
very  much  greater  as  velocity  increases  ;  and  the  runs  being 
very  long,  passengers  require  easier  seats,  even,  in  some 
cases,  accommodation  for  sleeping.  The  cost  for  repairs, 
therefore,  of  express  cars,  would  be  somewhat  greater  than 
for  any  others. 


MANAGEMENT.  431 


COST    AND    MAINTENANCE    OF    WAY   AND    WORKS. 

As  the  speed  is  increased,  the  relative  effect  of  grade  and 
curves  is  lessened,  but  the  absolute  danger  of  passing  curves 
is  increased.  Express  trains  require  larger  radius  of  curva 
ture,  or  greater  elevation  of  exterior  rail  than  others,  which 
extra  elevation  causes  an  unnecessary  resistance  to  all  other 
trains.  The  rails  to  resist  large  and  heavy  wheels  must  be 
heavier  and  more  firmly  fastened.  All  bridges  and  viaducts 
(particularly  if  on  grades  or  curves),  will  require  more 
strength  to  resist  the  increased  shocks  to  which  they  will  be 
subject.  The  wear  of  rails  is  nearly  as  the  weight  passing 
over  them  ;  the  wear  of  rails  consequent  upon  stopping  and 
starting  the  trains  depends  upon  the  momentum  of  the  train 
which  is  to  be  imparted  to  them. 

The  proportion,  in  which  the  working  expenses  are  dis 
tributed  under  the  several  heads  on  the  larger  railways  of 
Great  Britain,  is  as  follows  :  — 

Direction  and  management,   ....  7 

Way  and  works,        ......  16 

Locomotive  department,         ....  35 

Cars, 38 

Sundries,       .......  4 

Too 

And  the  percentage  of  increase  due  to  fast  travelling,  to  be 
applied  to  the  several  items  of  expense,  with  the  resulting 
increase  in  total  expense,  is  shown  below. 

Direction  and  management,          .  70=   0.0 

Way  and  works,     .         .         .         .  16     27=   4.3 

Locomotive  department,      .         .  35     30  =  10.5 

Cars, 38     10=   3.8 

Sundries, 4       0=   0.0 

TOO       18^6 
or  18  per  cent,  increase,  nearly. 


432  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

Express  trains,  as  worked  on  many  roads,  run  at  an  un 
necessary  speed,  to  make  up  for  frequent  stops.  Over 
coming  a  long  distance  in  a  short  time,  depends  as  much 
on  decrease  in  the  number  of  stops,  as  increase  in  the  speed. 

The  following  figures  show  the  effect  of  decreasing  the 
number  of  stops. 

A  train  running  400  miles,  and  stopping  once  in  fifty 
miles,  each  stop  being  five  minutes,  (including  coming  to 
rest  and  starting,)  to  pass  over  the  whole  distance  in  eight 
hours,  must  run  fifty-five  miles  per  hour. 

Stopping  once  in  twenty  miles,  sixty-three  miles  per  hour. 

Stopping  once  in  ten  miles,  eighty-six  miles  per  hour. 

The  following  table  shows  the  velocities  of  the  different 
classes  of  trains  in  England,  France,  and  Belgium,  including 
and  excluding  stops. 

EXCLUDING  STOPS. 
Express.     1st  class.        2d  class.        3d  class. 

England,     43.9       32.8         32.8         25.2  miles  per  hour. 

France,       27.5         24.3         28.1  " 

Belgium,     26.2         25.7         27.6  « 

INCLUDING   STOPS. 

Express.     1st  class.        2d  class.        3d  class. 

England,     36.5       24.8         24.8         17.5  miles  per  hour. 

France,       22.1         17.9         19.9  " 

Belgium,     20.7         19.3         18.1  « 

The  distances  at  which  the  different  classes  of  trains  stop 
in  the  several  countries,  are  as  follows :  — 

TRAINS    STOP   ONCE   IN 

1st  class.  2d  class.  3d  class.  Express. 

England,       8     miles,        8     miles,        5  miles,        24  miles. 
France,        10        "  6        «  6      «  —     « 

Belgium,       6.8     u  5.6     "  5     "  —     « 


MANAGEMENT.  433 


OF    THE    INCREASED    DANGER    OF    FAST    TRAVELLING. 

The  causes  of  accident,  beyond  the  control  of  passengers, 
are 

Collision  by  opposition. 

Collision  by  overtaking. 

Derailment  by  misplaced  switches  and  draws. 

Derailment  by  obstacles  upon  the  rails. 

Breakage  of  machinery. 

Failure  of  track  or  bridges. 

Fire. 

Boiler  explosions. 

Those  causes  which  are  aggravated  by  fast  travelling  are 
the  first,  second,  fifth,  and  sixth ;  the  effects  of  all  are  worse 
at  high  speeds  than  at  low. 

The  proportion  of  accidents  due  to  each  of  these  causes, 
taken  at  random  from  one  hundred  cases  on  English  rail 
ways,  are  as  follows  :  — 

Collision,       .         .         .         .         .         .         .         56 

Breaking  of  machinery,     .         .         .         .         .18 

Failure  of  the  road,       -j{\     .         .         .         .         14 

Misplaced  switches,  .....       5 

Obstacles  on  rails, 6 

Boiler  explosion,       ......       1 

loo 

In  collision  by  opposition,  the  engines,  tenders,  and  bag 
gage  cars  must  be  demolished  before  the  shock  reaches  the 
passengers ;  in  collision  by  overtaking,  the  engine  of  the 
rear  train  plunges  at  once  into  the  last  passenger  car  of  the 
leading  train  ;  the  force  in  the  last  case  is  the  difference  of 
the  speeds,  in  the  former  the  sum.  The  increase  of  danger 
from  this  cause,  attendant  upon  express  trains,  is  due,  first, 

37    ' 


434  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

to  the  longer  time  required  in  stopping,  and  second,  in  the 
greater  shock  if  collision  occurs. 

Breakage  of  machinery  is  more  liable  to  take  place  while 
wheels  are  revolving  25,000  times  per  hour,  than  when  the 
speed  is  less. 

Failure  of  the  superstructure  of  bridges,  (particularly 
when  on  curves  or  grades,)  is  more  liable  to  take  place  at 
high  than  at  low  velocities. 

Accidents  from  obstacles  upon  the  track,  from  fire,  boiler 
explosions,  and  misplaced  switches,  are  no  more  attendant 
upon  express  than  upon  other  trains,  but  the  consequences 
are  worse  with  the  high  speeds. 

From  the  analysis  above,  of  one  hundred  accidents,  it 
appears  that  eighty-eight  per  cent,  of  the  cases  are  due  to 
the  causes  that  are  aggravated  by  increase  of  speed,  and  if 
we  assume  the  aggravation  of  collision,  and  breakage  of 
machinery,  to  be  (speed  being  doubled)  as  two  to  one,  the 
danger  of  travelling  a  fixed  distance,  by  express,  is  eighty- 
eight  per  cent,  greater  than  by  a  slow  train. 


COMPARATIVE    COST    OF    WORKING    HEAVY   AND   LIGHT 

TRAINS. 

414.  The  question  is  sometimes  asked,  if  it  would  not  be 
better  to  run  a  greater  number  of  trains  and  reduce  the 
weight  of  engines.  A  comparison  of  cost  is  easily  made. 

The  cost  of  working  trains  consists  of 

Fuel,  oil,  and  waste. 
Engine-men's  wages. 
Wear  of  rails. 
Conductor  and  brakemen. 
Wear  of  cars. 


MANAGEMENT.  435 

Suppose  we  have  to  move  1,000  tons  per  day  over  any 
road.  If  we  do  it  by  one  engine  and  100  cars,  the  whole 
cost  will  be 

OneEngineer  .  f  .'f  f  .  .  ^  .  $2.00 
One  Fireman  .  •  •  •  -  -  1-50 
One  Conductor  .  .  "•  "V  "' ";'.'  '  .  '"/'  1.75 
Four  Brakemen  .  •  !  .  .  .  .  5.00 

$10.25 

And  if  we  move  1,000  tons  by  ten  trains  of  one  hundred 
tons  each, 

Ten  Engine-men  at  $2  .  .  .  .  $20.00 
Ten  Firemen  at  1J  .  • .  .  .  15.00 
Ten  Conductors  at  If  .  .  .  .  17.50 
Ten  Brakemen  at  1J  ....  12.50 

$65.00 

Difference  of  salaries  in  favor  of  the  heavy  train,  of  $54.75. 
As  the  whole  weight  upon  the  drivers  must  be  the  same 
to  move  a  given  load  by  either  method,  the  only  difference 
in  weights  of  engines  will  be  that  upon  the  truck.  To  lead 
well  a  truck  must  have  five  tons  upon  it.  The  whole 
weight  upon  ten  trucks  is,  then,  fifty  tons,  and  that  upon 
owe,  five  tons,  which  leaves  an  excess  of  forty  tons  to  be 
daily  carried  over  the  road  by  the  small  trains.  The 
heaviest  freight  engine  will  not  cost  over  $15,000 ;  the  cost 
of  an  engine  to  draw  one  hundred  tons  cannot  be  less  than 
$5,000. 

10  X  5000  =  50000  less  15000  is  $35000.   T{fo  of  35000  is  $2100. 

Add  to  this  five  times  as  much  fuel  used  in  firing  up  and 
standing  with  steam  up,  ten  times  as  much  oiling,  cleaning, 
and  repairing,  ten  times  as  much  engine  house  and  shop 
accommodation ;  also  that  the  cars  in  frequent  trains  are 


436  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

much  less  loaded  than  in  seldom  ones,  increased  delay  and 
chance  of  accident  from  increased  number  of  trains,  and 
estimating  all  of  them  at  $170.00  per  day,  (the  cost  of  the 
large  engine  being  assessed  at  $30  per  day,  and  that  of 
each  of  the  small  ones  as  $20,  the  daily  difference  is  $170,) 
and  we  have,  as  the  whole  daily  increased  cost  of  working 
ten  small  over  one  large  train, 


170.00  +  54.75  T°°  gg     -  or  6.71  =  $231.46  per  day, 

or    $72,446.98   per   annum,   which   employs   a   capital   of 
$1,207,449. 


BRANCH  ROADS. 

415.  These  lines,  when  belonging  to  the  main  road,  are 
generally  worked  at  a  loss ;  and  when  independent,  are  a 
poor  investment.  At  a  meeting  of  the  directors  of  the 
Boston  and  Worcester  (Mass.)  Railroad  in  February,  1855,  it 
was  declared  that  out  of  six  branches,  but  one  was  profit 
able.  That  four  of  them  gave  an  income  upon  cost  of  from 
one  and  a  quarter  to  one  and  three  quarter  per  cent. 

Independent  branch  lines  generally  share  a  joint  business 
by  the  mileage  standard ;  and  here  is  where  they  lose,  for 
if  the  branch  trains  do  not  traverse  the  main  line,  and  the 
tribute  passengers  help  to  fill  a  train  which  runs  at  any  rate 
upon  the  main,  then  the  branch  expense  of  carrying  the 
passengers  is  to  that  of  the  main,  as  (say' ninety  to  ten), 
and  the  branch  should  take  T9Q°a  of  the  receipts.  In  this 
case  the  branch  is  charged  with  using  both  the  cars  and 
road  of  the  main.  If  it  runs  its  own  cars  over  the  main, 
(as  when  the  branch  is  near  the  terminus,)  it  should  be 
charged  only  with  the  wear  of  the  road. 

In  like  manner  several  roads,  forming  a  continuous  line, 


MANAGEMENT.  437 

should  not  divide  the  receipts  according  to  the  mileage  ;  but 
according  to  the  cost  of  working  that  mileage.  Thus  if  we 
have  the  continuous  line  below,  column  one  shows  the 
length;  column  two,  the  cost  of  building;  column  three, 
that  of  maintaining  ;  and  column  four,  the  division  of  re 
ceipts.  , 


Division.  Length.        <*°°*       *%$$?* 


1  S  10  4  10  +  4   =  14 

296  3±  6  +  31=    91 

567  2|  7  +  2|=    9| 

4  10  4  1J  4+l£=   5± 


REPRODUCTION  OF  ROAD  AND  STOCK. 

416.  Besides  the  annual  repairs  necessary  to  maintain  a 
road  in  proper  working  order,  there  is  needed  a  periodic  ex 
penditure  for  reproduction.  Evidently  the  time  will  come, 
upon  all  roads,  when  rails  and  sleepers,  buildings,  bridges, 
etc.,  need  to  be  replaced.  Knowing  the  life  of  rails,  we 
also  know  the  annual  depreciation,  and  from  that  can  easily 
find  what  sum  must  annually  be  laid  aside,  which  being 
properly  invested,  shall,  at  the  end  of  the  life  of  the  rail,  to 
gether  with  its  interest,  be  equal  to  the  cost  of  renewing. 

RAILS. 

Suppose  rails  to  last  ten  years,  the  annual  depreciation  is 
ten  per  cent.  At  sixty  Ibs.  per  yard  we  have  one  hundred 
and  five  tons  per  mile,  which,  at  $60  per  ton,  amounts  to 
$6,300.  Let  the  cost  of  rerolling  and  relaying  be  $30  per 
ton,  the  depreciation  is  then  $30  per  ton  for  ten  years,  or 
$3  per  ton  per  annum,  or  $315  per  mile  per  annum, 

37* 


438  HANDBOOK   OP   RAILROAD    CONSTRUCTION. 


SLEEPERS. 

If  sleepers  last  seven  years,  and  cost  forty  cents  apiece, 
their  annual  depreciation  per  mile  (at  2,400  per  mile)  will 
be  $138  per  mile  (nearly). 

BRIDGES. 

If  wooden  bridges  cost  $30  per  lineal  foot,  and  last 
twenty  years,  the  annual  depreciation  per  foot  will  be  $1,50, 
and  if  there  is  ten  feet  per  mile  of  road,  $15  per  annum  per 
mile. 

EXTRAS. 

Allowing  for  the  annual  depreciation  per  mile  of  build 
ings,  fences,  etc.,  $33,  we  have  as  the  whole  annual  deprecia 
tion,  $500  per  mile ;  and  the  amounts  which  yearly  reserved 
and  placed  at  compound  interest  for  each  of  the  ten  years, 
will  pay  for  reproducing  the  road,  are  as  follows :  — 

At  the  end  of  the  1st  year  $298 


2d 

tt 

315 

3d 

u 

333 

4th 

u 

354 

5th 

u 

373 

6th 

« 

397 

7th 

u 

417 

8th 

u 

446 

9th 

tl 

472 

10th 

a 

500 

which,  at  six  per  cent,  gives,  at  the  end  of  the  tenth  year, 
$500  each. 

NOTE.  —  Reproduction  of  rolling  stock  has  been  proved  to  be  nothing  more 
than  repairs,  as  a  locomotive  may  be  fitted  with  one  and  another  new  part  until 
none  of  the  original  machine  remains.  See  Lardner's  Kailroad  Economy. 


MANAGEMENT.  439 

As  the  business  upon  a  railroad  increases,  so  does  the 
amount  of  station  accommodation  necessary,  and  also  of 
rolling  stock,  which  increase  should  be  debited  to  capital, 
and  not  to  revenue. 

The  permanent  investors  in  a  railroad  are  in  favor  of  hav 
ing  capital  maintained,  even  at  the  expense  of  revenue. 
The  temporary  shareholders,  and  the  speculators  in  stock, 
wish  most  to  produce  large  dividends,  even  at  a  sacrifice  of 
capital,  and  would  charge  nothing  to  revenue. 

The  rights  of  both  of  the  above  classes  are  to  be  regarded, 
as  the  road  is  often  built  mainly  by  the  efforts  of  the  tem 
porary  investors. 

WORKING  RAILROADS  BY  CONTRACT. 

417.  An  experiment  has  lately  been  tried  upon  the  work 
ing  of  railroads  which  bids  fair  to  reduce  very  considerably 
the  cost  of  operating ;  and  to  render  the  enterprises  more 
profitable,  namely,  working  the  several  departments  by  con 
tract  ;  that  is,  paying  certain  persons  a  fixed  price  for  sup 
plying  the  necessary  amount  of  power,  cars,  or  material  per 
annum,  thus  bringing  into  play  private  interest  and  indi 
vidual  enterprise.  There  is  no  doubt  but  that  by  a  judicious 
system  of  this  kind,  correctly  applied,  many  roads  which 
are  now  worthless  could  be  made  to  pay,  while  the  value  of 
good  roads  would  be  also  increased. 


CLASSIFICATION  OF  FREIGHT. 

418.  Freight  is  classified  according  to  its  nature,  the  com 
mercial  nature  of  the  country  traversed  by  the  road,  and  the 
direction  of  the  principal  market.  The  distribution  adopted 
upon  some  of  the  large  roads  is  as  follows :  — 


440 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


CLASSIFICATION    OF    ARTICLES. 


Double  First  Class. 
[Articles  marked  thus  *  at  owner's  risk.] 


Baskets,  *  Band  Boxes ; 

*  Camphene ; 

*  Carboys,  and  contents ; 

*  Demijohns,  and  contents; 
*Eggs; 

Feathers,  in  bags ; 
Furs; 


Hobby  Horses ; 

Musical  Instruments; 

*  Plaster  of  Paris,  (ornaments); 

Pictures,  in  frames ; 

Teazles,  in  casks; 

Wagons,  (children's); 

Willow  Ware. 


First  Class. 


*  Ale,  in  glass ; 

*  Apples,  green,  pre-paid; 
Bacon,  loose ; 

Batting ; 
Bells; 

*  Berries,  pre-paid; 

*  Blinds,  (window)  in  packages; 
Bonnets ; 

*  Books,  in  boxes; 
Boots; 

Bran,  in  bags ; 

Brass,  in  sheets  and  pigs; 

Brass  Castings; 

Brass  Vessels; 

Bread  and  Biscuit; 

Brooms,  in  bales  or  bundles; 

Broom  Handles,  in  boxes  or  bundles ; 

Brushes ; 

Buffalo  Robes,  packed; 

Buttons ; 

*  Candies  and  Confectionary,  canvassed ; 
Cane; 

Cards ; 
Carpeting; 
Caps; 

China  Ware; 
Chocolate ; 

*  Cigars,  in  boxes ; 
Cinnamon ; 

*  Clocks,  in  boxes ; 
Cocoa ; 

Cassia; 

Coffee,  ground; 

Collars ; 

Combs; 

Copper,  in  sheets  and  pigs ; 

Copper  Vessels ; 

Corks ; 

*  Cotton,  in  bales; 

*  Cotton  Waste ; 
Covers  and  Sieves; 

*  Cranberries; 


*  Cutlery; 

Deer  Skins,  in  bundles ; 
Doors ; 
Dry  Goods; 
Fancy  Goods; 

*  Figs,  in  boxes; 
Fire-arms ;      % 

*  Fish,  fresh,  pre-paid; 
Flour,  in  bags; 

Forks,  hay  and  manure ; 

*  Fruits,  fresh,  pre-paid; 

*  Game,  pre-paid; 
Garden  Seeds; 
Ginger; 

*  Glass,  in  boxes ; 

*  Glass  Ware,  in  boxes  or  casks ; 
Glue; 

*  Grapes,  pre-paid ; 

Gun  Stocks,  in  boxes  or  bundles ; 

Hair,  in  sacks ; 

Hams,  loose; 

Harness ; 

Hides,  dry; 

Hoe  Handles; 

*  Hollow  Ware; 
Honey; 


Hops,  pressed ; 
*  Ice,  pre-paid ; 


Indigo; 

Ink, 

Iron  Castings,  light ; 

Ivory ; 

Japan  Ware; 

Joiners  Work; 

*  Lemons,  in  boxes,  canvassed; 

*  Looking-glasses,  well  boxed ; 

*  Machinery,  boxed,  light; 

Marble,  wrought,  at  owner's  risk  of  break 
age; 
Mats; 

Mattrasses,  double,  at  150  pounds  each ; 
Mattrasses,  single,  at  100  pounds  each; 


MANAGEMENT. 


441 


Mill  Stuffs,  in  bags  or  casks ; 
Measures ; 

*  Meat,  fresh,  pre-paid ; 
Meat,  in  bulk,  salted; 
Medicines; 

*  Melons,  pre-paid ; 
Moss,  in  sacks; 

Nuts,  in  sacks  or  casks ; 

*  Oranges,  in  boxes,  canvassed,  pre-paid; 

*  Oysters,  in  cans  or  kegs ; 
Palm  Leaf,  in  bales ; 

Paper,  brown  wrapping  and  straw,  (light) ; 
Paper  Hangings ; 
Pelts ; 

*  Porter,  in  glass ; 

*  Poultry,  dressed,  pre-paid ; 

*  Prunes ; 

Rags,  (see  second  class); 

*Kaisins; 

Rake  Handles; 

Rattan; 

Rugs; 

Saddle  Trees; 

Saddlery; 

*  Sash,  in  packages ; 
Scale  Beams ; 
Scythe  Snaths; 
Shoes; 


Shovel  Handles ; 
Soap,  fancy; 
Soda; 
Spices ; 

*  Spirits  Turpentine ; 
Stationery ; 

Straw  Goods; 

Teas,  (see  third  class); 

Tin  Ware,  in  crates  or  hhds. ; 

Toys; 

Trunks,  empty,  80  pounds  each ; 

Tubs; 

Turners'  Work; 

*  Vegetables,  pre-paid ; 
Veneering; 
Wadding ; 

Warp,  on  beams ; 
Warp  Beams; 
Waste,  woollen ; 
Wax; 

Whalebone ; 
Wheelbarrows ; 
Whips; 
Wicking; 

*  Wines,  in  baskets  or  boxes ; 

*  Wooden  Ware; 
Wool; 
Woollens. 


Second  Class. 


Alcoholic  Liquors; 

*  Ale,  in  casks ; 
Apples,  dried; 
Alum; 
Anchors ; 
Anvils ; 

Ashes,  pot  or  pearl; 

Axes,  in  boxes; 

Axles,  iron; 

Bacon,  packed; 

Bagging; 

Barilla; 

Bark,  tanner's,  1£  cord  per  ton ; 

Beans; 

*  Beef,  in  casks  or  boxes ; 
Beer,  in  casks; 
Bleaching  Salts; 

Bones ; 

*  Bottles,  packed,  (empty); 
Brimstone ; 

Burr  Blocks ; 

Burlaps,  in  original  packages; 

*  Butter,  in  firkins; 

*  Candles,  in  boxes ; 
Cannon ; 

Canvas ; 

Castings,  heavy; 

Cement; 

Chains; 

Chalk; 

Chair  and  turned  Stuff,  in  bales  or  bdls. ; 

Cider,  in  casks ; 


Cheese,  in  boxes  or  casks ; 

Clay,  Coal,  and  Coke,  in  casks  or  boxes ; 

Clover  Seed; 

Coffee,  in  sacks ; 

Copperas ; 

Cordage ; 

Crockery  Ware,  well  packed ; 

Domestics,  in  original  packages ; 

Dye  Stuffs,  in  woods; 

Earthen  Ware,  well  packed; 

*  Fire  Brick ; 

Fish,  dried  or  salted; 

Flax  Seed; 

Flocks ; 

Floor  Cloth,  painted; 

Flour,  in  barrels,  20  barrels  or  less ; 

Furnaces ; 

Grain,  of  all  kinds ; 

*  Grindstones ; 

Groceries,  generally  heavy,  not  otherwise 

specified; 
Gunnies,  in  bales ; 
Hoes; 
Hams,  shoulders   or  sides,   in   casks  or 

boxes ; 
Hardware,  except  Cutlery; 

*  Hemp,  in  bales ; 
Hemp  Seed ; 

*  Hides,  green; 

*  High  Wines ; 

Hoops,  shaved  or  split,  3,000  pounds  per 
cord; 


442 


HANDBOOK   OF  RAILROAD   CONSTRUCTION. 


India  Rubber; 

Iron,  pig,  bloom,  boiler,  rod,  and  bar; 

Iron,  hoop,  sheet,  or  bolts ; 

Iron,  nuts,  rivets,  and  spikes ; 

Junk; 

Lard,  in  barrels  or  casks ; 

Lead,  sheet,  pig,  or  pipe ; 

Leather; 

Liquors,  in  barrels  or  casks ; 

Lime,  in  barrels  or  casks ; 

Marble,  unwrought,  at  owner's  risk  of 

breakage ; 

Meal,  in  bags  or  casks ; 
Molasses ; 
Moss,  pressed ;  • 
Nails,  in  kegs ; 
Oakum,  in  bales; 
Oil,  owner's  risk  of  leakage; 
Oil  Cake, 
OilCloth; 

*  Oysters,  in  shell  $ 
Paints,  dry  or  in  oil; 

Paper,  (white,)  in  boxes  or  bundles; 

Paper,  (heavy  brown  and  hardware); 

Pasteboard ; 

Pepper; 

Peaches,  dried; 

Peas,  in  sacks  or  casks; 

Pickles,  in  casks ; 

*  Pipes,  in  boxes ; 
Pitch; 

Plaster,  in  casks  or  barrels ; 
Ploughs ; 
Pork,  packed; 

*  Porter,  in  casks ; 
Potatoes,  in  casks  or  sacks; 
Rags,  foreign,  pressed; 
Rakes ; 

Railroad  Chairs  and  Spikes ; 

Rice; 

Rope; 

Rosin ; 

Saleratus ; 

Salt,  in  bags  or  casks ; 


Saltpetre ; 

Scales,  in  boxes; 

Scythes,  in  bundles ; 

Scythe  Stones; 

Shot,  in  bags ; 

Shovels  and  Spades ; 

Sizing; 

Slate* 

Soap,  (common,)  in  boxes; 

Soda: 

Spelter  and  Zinc; 

Spikes,  in  kegs ; 

Spirits,  domestic; 

Starch ; 

Steel,  in  boxes  or  bundles; 

Steel  Springs; 

Stone ; 

*  Stone  Ware,  well  packed ; 
Sugar ; 

Sumac; 

Tallovr,  owner's  risk  of  heat ; 

Tar; 

Tiles; 

Tin,  metal  and  plate; 

Tobacco,  in  bales,  boxes,  or  hhds. ; 

Tow,  pressed,  (in  bales,)  owner's  risk  of 

fire; 

Twine,  in  bales ; 
Vegetable  Roots,  in  sacks  or  casks ; 

*  Vinegar; 
Water,  Mineral; 
Whiskey,  in  casks ; 
White  Lead; 
Whiting; 

*  Wine,  in  casks ; 
Wire,  in  rolls  and  casks ; 
Woods,  in  shape,  unfinished ; 

Woods,  of  value,  namely,  Mahogany, 
Lignum  Vitae,  Rosewood,  Cherry,  Ce 
dar,  Walnut,  etc. ; 

Wool,  foreign,  pressed,  in  bales ; 

Yarn,  pressed; 

Zinc  and  Spelter. 


Third  Class. 


Includes  the  following  articles  in  quantities  of  8,000  pounds,  and  less  than  16,000 
pounds,  in  any  one  shipment  from  one  consignor  to  one  consignee.  Same  articles 
shipped  in  like  manner,  in  quantities  of  16,000  pounds  and  upwards,  will  be  taken 
at  special  rates. 


Anchors ; 

Anvils ; 

Ashes,  pot  and  pearl,  in  casks ; 

Axes,  iron; 

Bacon,  packed ; 

Bark,  tanner's,  l£  cord  per  ton; 

Beans,  in  sacks  or  casks ; 

Beef,  packed ; 

Burr  Blocks; 

Cannon ; 


Cement,  in  barrels  or  casks ; 

Chain  Cable; 

Cider; 

Clay; 

Coffee ; 

Copper,  in  boxes ; 

Flaxseed,  in  sacks  or  casks; 

Flour,  in  barrels ; 

Grain,  of  all  kinds; 

Grindstones ; 


MANAGEMENT. 


443 


Hams,  packed; 

High  Wines; 

Iron,  pig,  bar,  bloom,  sheet,  hoop,  or  rod ; 

Iron  Castings,  heavy; 

Lard,  in  casks  or  barrels ; 

Lead,  sheet,  pig,  or  pipe ; 

Lime,  in  barrels ; 

Marble,  unwrought,  at  owner's  risk  of 

breakage ; 

Molasses;  •«  /  ^ 

Nails,  in  kegs ; 
Plaster,  in  barrels ; 


Pork,  packed; 

Potatoes,  in  sacks  or  casks ; 

Railroad  Iron,  Chairs  and  Spikes; 

Salt,  in  sacks  and  barrels ; 

Shot; 

Slate; 

Spikes,  in  kegs ; 

Sugar,  in  casks ; 

Teas; 

Tobacco,  in  boxes  or  hhds. ; 

Vinegar,  in  barrels ; 

Whiskey,  in  barrels. 


Besides   the   above   regular   articles,   are   the   following 
special  objects  of  transport :  — 


Stores ; 

Cabinet  Ware ; 
Brick; 
Charcoal ; 
Pressed  Hay; 
Broom  Corn; 
Boxes  of  Cigars 
Barrels ; 


Corn  in  the  Ear 
Poultry; 


Looking-glasses  ; 

Trees  and  Shrubbery; 

Safes; 

Mill-stones ; 

Steam-engines ; 

Machinery ; 

Agricultural  Implements ; 

Lumber ; 

Live-Stock; 

Carriages ; 

Coal  and  Coke. 


TIME  TABLES. 
Fig.  158,  (see  end  of  volume). 

419.  The  most  complete  graphic  valuation  of  an  engi 
neering  problem,  is  doubtless  the  time  table  of  S.  S.  Post, 
Esq.,  chief  engineer  of  the  New  York  and  Erie  Railroad. 
Let  the  vertical  lines  represent  time  in  spaces  of  ten  minutes 
each,  and  the  horizontals,  distances,  the  heavy  lines  repre 
senting  the  several  way  stations.  Suppose  now  that  we 
leave  station  A  at  six,  A.  M.,  and  wish  to  arrive  at  K  at  two, 
p.  M.,  stopping  ten  minutes  at  each  station ;  the  number  of 
way  stations  being  eight,  the  whole  time  consumed  in  stops 
will  be  10  X  8  =  80  minutes.  From  two,  p.  M.,  and  on  the 
line  K,  go  back  eighty  minutes  or  to  M,  and  from  A  draw 
A  B,  in  the  direction  A  M,  which  cuts  the  line  B  B  at  B, 
which  is  four  miles,  or  thirteen  minutes  from  A.  Now,  as 


444  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

we  wait  ten  minutes,  pass  along  on  the  line  B  B  one  division 
(ten  minutes)  to  B'  and  start  again  parallel  to  A  B,  arriving 
at  C  at  one  and  a  half  hours  from  starting.  Proceeding 
thus,  we  arrive  at  K  at  the  required  time.  The  inclination 
of  the  line  shows  the  speed.  Thus,  if  it  passes  twenty 
horizontal  spaces  in  six  vertical  divisions,  we  have  twenty 
miles  in  sixty  minutes,  or  twenty  miles  per  hour. 

Suppose  now  we  would  start  an  express  train  at  eight, 
A.  M.,  from  A  to  arrive  at  K  at  one,  p.  M.,  (see  line  8  F,)  it 
will  pass  the  first  train  at  station  F,  and  will  run  at  the  rate 
of  seventeen  miles  per  hour  from  A  to  F,  at  the  same  rate 
from  F  to  G,  and  at  thirteen  miles  per  hour  from  G  to  1. 

Suppose  also  that  we  start  a  train  from  K  at  six,  A.  M.,  to 
arrive  at  A  at  eleven,  A.  M.,  we  pass  the  before-mentioned 
trains  at  E  and  D. 

Also  a  freight  train  which  is  required  to  pass  the  above- 
named  trains,  leaving  K  at  eight,  A.  M.,  and  arriving  at  A  at 
one,  P.  M.,  will  stop  ten  minutes  at  G,  ten  minutes  at  M, 
pass  the  first  train  at  L,  wait  ten  minutes  on  a  siding  at 
two  and  a  half  miles  from  L,  and  run  to  A  at  nearly  a  uni 
form  rate  of  speed. 

So  also  may  the  motion  of  any  train  be  laid  down  and 
traced  through  the  hours  of  the  day  upon  the  table.  By 
plotting  the  profile  of  the  road  upon  the  line  A  K,  the  places 
are  shown  at  which  grades  will  oblige  us  to  use  a  less  speed. 
Curves  also  may  be  shown  by  increasing  the  steepness  of 
the  grades ;  or  by  making  a  grade  on  the  profile  when  the 
road  is  level,  steep  enough  to  involve  an  amount  of  power 
equal  to  that  consumed  by  the  curve. 

LOCOMOTIVE    REGISTERS. 

420.  American  railroad  reports  are,  as  a  general  thing, 
quite  destitute  of  detailed  accounts  of  the  performance  of 


MANAGEMENT.  445 

the  power.  Some  of  the  large  roads,  indeed,  are  of  late 
improving  in  this  respect. 

That  fares  and  tolls  may  be  properly  applied  to  the  differ 
ent  articles  of  transport,  the  cost  of  moving  each  article 
should  be  known. 

Such  items  as  the  salaries  of  employees,  and  repairs  of 
machinery,  are  easily  distributed  to  the  proper  heads ;  but 
the  correct  amount  of  fuel,  oil,  and  waste,  to  be  charged  to 
any  department,  is  not  so  evident.  What  we  require  is, 
the  exact  amount  of  fuel,  oil,  and  waste  used,  and  work 
done  by  each  engine ;  to  obtain  which,  some  system  of 
registering  these  quantities  must  be  adopted. 

The  following  five  blanks  being  filled,  we  have  all  that  is 
required :  — 

Number  1  is  the  engineer's  weekly  return  to  the  master 
of  machinery,  and  gives,  as  seen,  the  times  of  arriving  at, 
and  departing  from,  each  station.  The  fuel  should  always 
be  ready  at  each  station  for  delivery,  in  cords  and  half  cords, 
or  in  tons  and  fractions,  when  coal  or  coke.  It  may  be  de 
livered  either  from  a  small  car  placed  on  a  pair  of  rails  at 
right  angles  to  the  track,  or  from  a  box  hung  upon  a  crane, 
which  may  be  at  once  swung  over  and  lowered  into  the 
tender;  the  box  which  is  already  in,  being  first  removed. 
The  latter  method  gives  the  most  correct  results,  as  what 
ever  fuel  is  left  at  the  station  may  be  credited  to  the  engine. 
The  whole  operation  of  wooding  would  not  take  longer 
than  it  does  to  describe  it,  and  would  lead  to  a  systematic 
and  economical  method  of  working. 

The  tanks  and  -pumps  being  charged  to  construction,  we 
may,  without  material  error,  charge  the  cost  of  the  water 
supply  to  the  trains  according  to  their  mileage. 

Number  2  is  the  wood  register,  showing  the  amount  of 
fuel  delivered  to  the  several  engines  from  the  different  sta 
tions,  and  should  be  weekly  signed  and  returned  by  the  sta- 

38 


446  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

tion  wood  master  to  the  fuel  agent.  The  engineer's  fuel 
receipts  (No.  1)  check  these  reports. 

Number  3  is  the  conductor's  mileage  account,  giving 
the  exact  weight  left  at,  and  taken  from,  each  station ;  and, 
consequently,  the  load  carried  between  stations,  which  is 
checked  by  the  station  master's  return. 

Number  4  is  the  monthly  account  of  the  performance 
of  engines,  compiled  from  the  weekly  return  by  the  superin 
tendent  of  machinery,  and  reported  to  the  superintendent. 

Number  5  gives  the  annual  performance  of  each  and 
all  of  the  engines  upon  the  road,  and  is  attained  from  the 
monthly  reports,  and  from  those  of  the  repair  and  transpor 
tation  departments. 

The  work  done  by  different  classes  of  cars  should  be 
registered  in  like  manner. 

Knowing  the  amount  of  material  used,  and  also  the  work 
done,  it  is  easy  to  find  the  cost  per  mile  of  moving  any 
article  of  transport,  regard  of  course  being  had  to  the  char 
acter  of  the  parts  of  the  road  traversed  by  the  several  en 
gines.  An  engine  working  a  sixty  feet  grade  should  be 
allowed  more  fuel  than  one  which  works  a  level  only. 


MANAGEMENT. 


447 


NUMBER  1. 

A.  and  B.  Railroad.  Report  of  amount  of  material  con 
sumed,  and  of  work  done  by  Engine  No.  50,  during  the 
week  ending  July  4,  1856. 

,  Engineer. 


MONDAY. 

Name  of  train. 

Name  of  station. 

1 

Time  of  arriving. 

Time  of  departing. 

Fuel  taken. 

Whole  cost  fuel  consume 
Whole  time  under  steam 
Whole  time  running 

d       



And  the  same  for  each  day  of  the  week. 


WEEKLY   MEMORANDA. 


Cords  of  wood  used 
Gallons  oil  used 
Pounds  tallow  used 
Pounds  waste  used    . 
Miles  run 

Whole  time  running 
Whole  time  under  steam 
Time  under  repairs 
Cost  of  repairs     !. 


-,  Master  of  Machinery. 


448 


HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


NUMBER  2. 


MANAGEMENT. 
NUMBER  3. 


449 


A.  and  B.  Railroad.  Conductor's  mileage  return,  for 
week  ending  July  4,  1856,  showing  work  done  by  Engine 
No.  54. 


Train. 


Station. 


Cars  taken. 


Cars  left. 


Cars  in  train. 


Weight  of  train. 


Eq'd  distance. 


Eq'd  mileage. 


Total  equated  mileage 


And  the  same  for  each  day  of  the  week. 


450  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

t 
NUMBER  4. 


A.  AND  B.  RAILROAD.  PERFORMANCE  OF  LOCOMOTIVE  ENGINES  FOR  MONTH  ENDING  . 

•aaop  : 

[JOA  -draoo 

• 

,  General  Superintendent. 

6 

1 
1 

I 

flP 

}|{i 

i 

fiP 

1  s  i 

02 

I 

•aitra  jad  ijsoo 

n»o 

1 
S 

•3\im  aad  4303 

•^oo 

IB 

0 

1 

§ 

'a^SBAi    '[tO   JO 

eijai  aad  ^sog 

PUB  'a^suM. 
'jio  jo  !jsoo 

jo  spunoj 

jo  spunoj 

a,d'°]?,K 

•pasn 
lio  suon«o 

1 

•pjoo 
jad  sdUK 

•8pao0 

1 

•a{ira  aad  ^SOQ 

•?8o0 

I 
H 

•SJIBd 

-aj  japafi 

-,Saj,y 

•gapiJO^ 

•uru  sanm 

•asfl 

•jaqamjH 

MANAGEMENT. 
NUMBER  5. 


451 


A.  AND  B.  RAILROAD.  ANNUAL  REPORT  OF  COST  OF  MAINTENANCE  OF,  AND  WORK  DONE  BY  THE 

I 

3 

1 

i 

H 

§ 
• 

fc 
O 

| 

E 

ft 

B 

<J 

M 

13 

1 

1 
O 

i£ 

a> 

3 

M 

•aaguo  ?sBiq 
jo  «aay 

.I   1 

•aoBjing 
3u»TOq 
»[oqAi 

Bb     H 

RECAPITULATION,  No.  2. 
Cost  per  equated  mile,  per  passenger,  of  working  e 
Engineer  and  fireman.  Fuel.  Oil,  tallow,  and  waste.  Repairs. 

•«3J«  OJBJf) 

•sqi  Si  Jo 

ainssajd  japai[ia 
UBera  B  ^u  uoi)3va-|  JO 

'j3MOd  3A^B[3}r 

as 

1 

J* 

> 

g 

•M^aotBid 

•jaqran^j 

•uonaaaaoa  jo  apojg 

s 

T3 

a 
I 

•a^oj^g 

•ajoq 
jo  ja^aujBid 

^  I         a 

11*1 

a    ^         a 

RECAPITULATION,  No.  1. 
Cost  per  equated  mile,  per  ton,  of  working  freight  engines. 

Engineer  and  fireman.  Fuel.  OU,  tallow,  and  waste.  Repairs.  Total. 

i 

i 

i 

Ut" 

i! 

•§!s3*B 

|  -SUja  2  1 

£fsf" 

if  i  i  i 

"            0                            0 

J  V  *  1 

1  !  i  I  i  4 
LJJjJJ 

:aui3aa  aq»  jo  «qnmu  ao  anreji 

452  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 

NUMBER  5,  Continued. 


1 

LOCOMOTIVE  POWER,  ALSO  THE  COST  PER  TON  AND  PASSENGER  PER  MILE,  TOGETHER  WITH  THE 

to 
O 

W 
1 

1  *  1  *  1 

KECAPITULATION,  No.  4.. 
Same  as  3  ;  for  passenger,  in  place  of  freight  engines. 

MHI 

WHOLE  EXPENSE  OP  WORKING  AND  OF  MAINTAINING  THE  LOCOMOTIVES,  AND  EXPENSE  PER  MILE. 

I 

i!^ 

e!| 

l! 

Jj 

PH 

O 

M 

t,  a     "g  . 
^.2,»§ 

is*!,!1 

»S     £* 

S|j 

il'o 

J|i 

"w 

<S 

1 
0 

«! 

o  S<2 

',4 

jJ 

"o 

£ 
g-s| 

O  T3 

?-  a 

11 

»:j 

co     .5  «  S 

^*«  ^ 
6      S  °« 

J25         ^^d   C8 

*  -sgfr 

2     £  ^^ 
5     s  SF-S 

^             «  g 

t>        E 

a    i^, 
i  'NlS 

M      §f  *« 

III 

*<jsj| 

iiir 

Sfsl 

O)    eg   eS 
O.'C    OH 

kc 

5 

i 

c3 

oT 

1 

'o 

1 

1 

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Mf^g 
ItlPI 

61"      s 

|f||| 

a>  ^ 

111 

Hi 

life 

all's 

o 

!;i 

spj 

|ljj 

a    *    JS     « 

1  1  1  s 

MANAGEMENT. 
NUMBER  5,  Continued. 


453 


NATURE  AND  AMOUNT  OF  REPAIRS,  THE  DIMENSIONS,  &  THE  PRESENT  STATE  OF  THE  STOCK,  1856. 

*      * 

a      a      S 
«       o       a 

Ml 

Gen'l  Superintendent. 

i! 

o 

1     i 

1  1  1 

1         * 

1    |    I 

ju 

RECEIPTS,  OR  AMOUNT  OF  WORK  DONE  BY  LOCOMOTIVES. 

as 

a 

1 

1 

s 

!.d, 

&|*i 

flj1 
*3 

Hi 

S-g^ 

RECAPITULATION,  No.  5. 

Relative  cost  per  equated  mile  of  gross  to  net  tons  of  freight 
carried.  Relative  cost  per  equated  mile  of  gross  to  net  tons 
of  passengers  carried. 

Merchandise. 

:^i 

|||2 

^sjl 

I  111 

K«OJ 

S3  «-i  *» 

Hii 

•g  —  S  «* 

11*" 

P§3 

ill'9 

|H 
O 

to 
a 

PH 

ifc 

P'§ 

ell 

Ml 

SERVICE. 

V 

III 

454  HANDBOOK   OF   RAILROAD    CONSTRUCTION. 


TELEGRAPH. 

421.  The  magnetic  telegraph  has  lately  come  into  use  as 
a  means  of  communication  along  the  lines  of  long  railroads, 
and  nothing  serves  better  the  purposes  of  adjusting  the 
movement  of  trains,  of  transmitting  orders,  and  of  keeping 
the  general  superintendent  informed  at  all  hours,  of  the 
exact  condition  in  detail  of  the  whole  road,  and  of  all  its 
trains.  The  following  is  extracted  from  Mr.  Mc'Callum's 
Report,  before  referred  to :  — 

"  A  single  track  railroad  may  be  rendered  more  safe  and 
efficient,  by  a  proper  use  of  the  telegraph,  than  a  double 
track  railroad  without  its  aid,  —  as  the  double  track  can 
only  obviate  collisions  which  occur  between  trains  moving 
in  opposite  directions,  whilst  the  telegraph  may  be  used 
effectually  in  preventing  them,  either  from  trains  moving  in 
an  opposite,  or  the  same  direction  ;  and  it  is  a  well  established 
fact  deduced  from  the  history  of  railroads,  both  in  Europe 
and  in  this  country,  that  collisions  between  trains  moving 
in  the  same  direction  have  proved  by  far  the  most  fatal  and 
disastrous,  and  should  be  the  most  carefully  guarded  against. 
I  have  no  hesitation  in  asserting,  that  a  single  track  rail 
road,  having  judiciously  located  turnouts,  equal,  in  the  ag 
gregate,  to  one  quarter  of  its  entire  length,  and  a  well- 
conducted  telegraph,  will  prove  to  be  a  more  safe  and 
profitable  investment  than  a  much  larger  sum  expended 
in  the  construction  of  a  continuous  double  track,  operated 
without  a  telegraph. 

"  Collisions  between  fast  and  slow  trains,  moving  in  the 
same  direction,  are  prevented  by  the  application  of  the  fol 
lowing  rule  :  — l  The  conductor  of  a  slow  train  will  report 
himself  to  the  superintendent  of  the  division,  immediately 
on  arrival  at  a  station  where  by  the  time  table  he  should  be 


MANAGEMENT.  455 

overtaken  by  a  faster  train ;  and  he  shall  not  leave  that 
station  until  the  fast  train  passes,  without  special  orders 
from  the  superintendent  of  the  division.'  A  slow  train 
under  such  circumstances,  may,  at  the  discretion  of  the 
division  superintendent,  be  directed  to  proceed.  He,  being 
fully  apprised  of  the  position  of  the  delayed  train,  can  readily 
form  an  opinion  as  to  the  propriety  of  doing  so,  and  thus, 
whilst  the  delayed  train  is  permitted  to  run  without  regard 
to  the  slow  train,  the  latter  can  be  kept  entirely  out  of  its 
way. 

"NOTE.  —  In  moving  trains  by  telegraph,  nothing  is  left  to  chance.  Orders 
are  communicated  to  the  conductors  and  engineers  of  the  opposing  trains,  and 
their  answers  returned  giving  their  understanding  of  the  order  before  either  is 
allowed  to  proceed. 

"  Their  passing  place  is  fixed  and  determined,  with  orders 
positive  and  defined  that  neither  shall  proceed  beyond  that 
point  until  after  the  arrival  of  the  other ;  whereas,  in  the 
absence  of  a  telegraph,  conductors  are  governed  by  general 
rules  and  their  individual  understanding  of  the  same  ;  which 
rules  are  generally  to  the  effect,  that  in  cases  of  detention, 
the  train  arriving  first  at  the  regular  passing  place,  shall, 
after  waiting  a  few  minutes,  proceed  cautiously,  '  expecting 
to  meet  the  other  train,'  until  they  have  met  and  passed,  the 
one  failing  to  reach  the  *  half  way  post '  between  stations 
being  required  to  back  (always  a  dangerous  expedient), 
and  the  other  permitted  to  proceed;  the  delayed  train 
being  subjected  to  the  same  rule  in  regard  to  all  other  trains 
of  the  same  class  it  may  meet,  thus  pursuing  its  hazardous 
and  uncertain  progress  during  the  entire  trip.  The  history 
of  such  a  system  furnishes  a  serious  commentary  on  the 
imperfection  of  railroad  regulations. 

"  The  liability  to  collision  under  the  system  referred  to 
has  prompted  the  invention  of  various  expedients  for  sud- 


456  HANDBOOK   OF  RAILROAD   CONSTRUCTION. 

denly  arresting  the  progress  of  trains ;  and  which  seem  to 
have  been  conceived  under  the  impression,  more  imaginary 
than  real,  that  the  difficulties  they  were  designed  to  obviate, 
are  unavoidable  in  their  character;  but  which  may,  by  the 
exercise  of  ordinary  care  and  the  use  of  the  telegraph,  be 
subjected  to  perfect  control.  Some  of  these  inventions  un 
doubtedly  possess  sufficient  merit  to  entitle  them  to  adoption 
under  any  circumstances,  whilst  others,  for  the  above  rea 
sons,  are  entirely  valueless  —  indeed  it  is  questionable 
whether  a  reliance  on  their  use  may  not  in  many  cases  lead 
to  danger,  by  producing'  recklessness,  and  thus  increase  instead 
of  diminish  the  evils  sought  to  be  avoided" 


NEW  YORK  AND  ERIE  RAILROAD. 

422.  As  a  fine  specimen  of  American  railroad  engineering, 
and  American  railroad  management,  stands  the  above- 
named  line,  extending  from  Jersey  City  to  Lake  Erie,  at 
Dunkirk ;  embracing  with  its  branches  496  miles  of  road, 
employing  over  1,000,000  dollars  worth  of  labor  per  annum, 
upwards  of  200  locomotive  engines,  and  about  3,000  cars ; 
earning  annually  over  5,000,000,  and  expending  2,680,000 
dollars. 

The  whole  cost  of  the  road  up  to  September  30,  1855, 
was,  with  the  equipment,  nearly  $33,750,000.  There  are 
129  truss  bridges,  amounting  in  all  to  15,692  feet  in  length ; 
64  trestle,  stringer,  and  pile  bridges,  of  5,489  feet  total  length ; 
3  viaducts,  of  length  1,274  feet  in  all ;  167  arch  culverts,  of 
from  3  to  30  feet  span ;  527  box  culverts,  from  1  to  12  feet 
span ;  92  wood  sheds,  14,200  feet  total  length ;  435  build 
ings  ;  433  switches,  of  387,914  feet  available  length,  and 
£04,205  feet  total  length. 

Notwithstanding  the  immense  amount  of  business  trans- 


MANAGEMENT.  457 

acted  by  such  a  road,  so  complete  is  the  organization  and 
management  of  employees,  that  the  general  superintendent, 
sitting  in  his  New  York  office,  can  at  any  moment  tell, 
within  one  mile,  where  each  car  or  engine  is,  what  it  is 
doing,  with  what  loaded,  the  consignor  and  consignee,  and 
the  time  of  arriving  and  departing  the  several  stations,  and 
other  trains ;  and  thus  at  any  moment  may  perceive  and 
correct  faults  and  remissness,  and  in  reality  control  the 
whole  road. 


39 


APPENDIX, 


A. 


DECIMAL     ARITHMETIC. 

THE  advantage  of  a  Decimal  system  of  Arithmetic  and  of  men 
suration,  as  applied  to  engineering,  can  hardly  be  overstated.  Civil 
and  mechanical  engineers  both  use  "  per  force  "  some  decimal  ex 
pressions,  as  0.7854,  3.1416,  etc.,  etc.  Why  not  adopt  the  system 
entirely  ?  All  calculations  are  much  easier  made  decimally,  and  men- 
surements  made  with  more  exactness.  The  most  perfect  system  of 
weights  and  measures  is  doubtless  that  of  the  French.  All  lengths 
are  based  upon  the  meter  as  a  unit,  and  whether  the  mechanic  is 
making  a  watch  or  a  locomotive  his  scale  is  metrical.  The  meter 
is  exactly  nnyoWuo-  °f  tne  distance  from  the  pole  to  the  equator, 
and  was  found,  by  measuring  a  meridian  line  from  Rhodes  to  Dun 
kirk  (France),  570  miles  long.  The  metrical  scale  is  thus, 

Millimetre     .....         .001  or  y^j^ 

Centimetre 01    or   y^ 

Decimetre      .         .         .         .         .         .1      or    ^ 

Metre 1. 

Decametre  .  .  .  .  .10. 
Hectametre  .  .  .  .100. 
Ridometre  ....  1000. 
Myriametre  ....  10000. 


460  APPENDIXf 

The  metre  is  3.280899  ft.,  or  39.370788  English  inches.  The  Eng 
lish  and  American  foot  is  ^  of  the  yard ;  the  yard  is  f  f  f§iS  °f  a  Pen~ 
dulum  vibrating  seconds  at  the  latitude  of  London,  at  the  level  of 
the  sea,  in  a  vacuum.  The  standard  American  scale  is  an  eighty- 
two  inch  bar  made  by  Troughton  of  London  for  the  United  States 
Coast  Survey.  In  civil  engineering  the  decimal  division  is  almost 
entirely  adopted ;  indeed,  any  other  would  lead  to  almost  endless 
calculation.  The  chain  is  one  hundred  feet  long  and  divided  into 
one  hundred  links.  The  tape  is  graduated  to  feet,  tenths,  and  hun- 
dredths.  The  levelling  rod  to  feet,  tenths,  hundredths,  and  thou 
sandths.  As  the  English  foot  is  so  universally  adopted,  and  as  it 
may  at  any  time  be  got  from  a  pendulum,  it  might  not  be  best  to 
attempt  to  introduce  the  metre,  but  the  foot  should  certainly  be 
divided  decimally.  The  division  should  be  thus, 

.001  or 

.01    or 

-1      or   TV 

1. 

10. 

100. 

1000. 

thus  preserving  a  constant  ratio,  and  not  changing  the  proportion  at 
each  increase  or  decrease  as  follows :  — 

f  =  1  inch. 
12  inches  =  1  foot. 
16^  feet  =  1  rod. 
40  rods  =  1  furlong. 
8  furlongs  =  I  mile. 
3  feet  =  1  yard. 
6  feet  =  I  fathom. 


APPENDIX.  461 


B. 


ALGEBRAIC    FORMULAE. 

As  this  work  may  come  into  the  hands  of  those  who  are  unac 
quainted  with  the  solution  of  algebraic  problems,  it  was  thought  best 
to  give  the  following :  — 

a  -\-  a,  signifies  a  added  to  a,  or  2  «. 

a  —  a,  denotes  a  less  than  a,  or  0. 

a  X  a,  a  multiplied  by  a,  or  a  square,  a2  (see  below). 


«-^-<O 

a      \-a  divi 

°V  J 


divided  by  a,  or  1. 


a  2,  the  square  of  a,  or  a  X  <*• 

a  8,  the  third  power  of  a,  or  a  X  «  X  o,. 

\/a,  the  square  root  of  a,  or  a  % 

y/a,  the  cube  or  third  root  of  a,  or  a  *. 

"*  — ,  shows  that  the  sum  of  a,  &,  and  e,  is  to  be  divided  by  <L 

(a  _|_  J  _|-  c)  rf  or  a  -f-  6  -j-  c  X  ^5  denotes  that  the  sum  of  «,  &,  and 

c,  is  to  be  multiplied  by  d. 

Generally  in  place  of  writing  a  X  &  to  express  multiplication,  we 
put  simply  a  b. 

The  above  signs  may  be  compounded  in  any  manner ;  thus, 


Here  we  have,  first,  the  product  of  c  by  the  sum  of  a  and  b ;  this 
is  divided  by  c?,  and  three  quarters  of  the  quotient  is  divided  by  m  ; 
and,  finally,  the  fourth  root  of  the  last  result  is  extracted,  which  is 
the  value  of  the  expression. 

The  following  examples  show  the  use  of  formulae.  See  Chapter 
VL,  on  Earthwork,  art.  Average  Haul:  — 

39  ' 


462  APPENDIX. 

Required  the  average  haul  of  several  masses  of  earth.  Let  m 
m'  m"  mn  represent  the  several  masses,  and  d  d'  d"  dn  the  respective 
hauls  ;  £  the  sum  of  the  masses,  D  the  average  haul,  and  we  have 


If  we  make  the  values  m  =100  also  d  =.  100 
mf  =  200  d'  —  50 
m"  =  300  d"  =  75 
mn  =  400  dn  =  200 

the  sum  is  1000,  and  we  have 

100  X  100  +  200  X  50  -f  300  X  75  -f  400  X  200  _ 
1000 

In  Chapter  VIIL,  Wooden  Bridging,  we  have  the  expression 


/ 

and  if  b  =  10 


and  I  =  20 
S  becomes 

4  X  10  X  144 


20 
In  Chapter  IX.,  Iron  Bridges,  we  have 


we  have 

4000  X  500 


and  making  p  =  4000 
h=  500 
/=  80 


UU  X  OUU      / 

2X80      y/500 2  +  (4  X  80 2)  =  6249900. 


APPENDIX.  463 


Iii  Chapter  XIII.,  Elevation  of  Exterior  Rail, 

W  V^\ 


w 

and  when  W  =      50 

F=      20 

<7  =        ^ 

R  =  2000 

we  have 


50 

And  finally,  in  the  latter  part  of  Chapter  XIV.,  we  have  the 
formula 


0.7 


and  making  w  =  200 
d=      2 


we  have 


D—    /[aoo(2 

V  0.7 


Now2rf  H^i 

25 
also,  200  X       —  1250, 


1250  X  o  —  1666» 
o 

1666  -^  0.7854  =  2121, 


854 

5\2is25 


finally,  V*2121  =  46  ver7  nearly. 


464 


APPENDIX. 


c. 


WEIGHTS    AND    MEASURES. 


Name  of  material. 
Air 
Earth 
Water  . 
Ice 

Sand     . 
Clay 
Chalk    . 
Brick 
Brickwork 
Dry  mortar 
Sandstone 
Limestone 
Granite 

Coal,  Bituminous  . 
Coal,  Anthracite 
Coke 

Coal,  Cannel    . 
Wrought  Iron 
Cast-Iron 
Steel 


Weight  per  cubic  foot. 

0.0  7  7  Ibs. 

.  112.         " 

62.5       " 

.     58.0       " 

132.0       " 

.  120.0       " 

155.0       " 

.  110.0 

95.0 

.     96.0 

140.0 

.  142.0 

175.0 

60  to  80.0 

85  to  95.0 

50  to  65.0 

75  to  80.0 

.  480.0 

450.0 

.  487.0 


,t  See  Chap.  XI., 
masonry. 


ti  Average  86  to 
198 

M 


Green  . 
Air  dried 
Kiln  dried 


Hard    Wood. 


62.0  Ibs. 
46.0  " 
40.0  " 


Green 
Air  dried 
Kiln  dried 


Soft  Wood. 


53.0  Ibs. 
30.0  » 
28.0  " 


Wheat 

Corn  on  the  cob 


Weight  per  bushel. 
60      Ibs. 
70       " 


APPENDIX. 


465 


Corn,  shelled  . 
Rye 
Oats 
Barley 

Potatoes,  Irish 
Potatoes,  Sweet 
Beans,  White  . 
Beans,  Castor 
Bran    . 
Clover  Seed 
Timothy 
Hernp 
Flax     . 
Buckwheat 
Peaches,  Dried 
Apples,  Dried 
Onions 
Salt,  Coarse 
Malt     . 
Corn  Meal 
Salt,  Fine 


Weight  per  bushel. 
56     Ibs. 

56 

M 

35 

It 

47 

ti 

60 

« 

55 

(C 

60 

" 

46 

11 

20 

11 

60 

It 

45 

It 

44 

It 

56 

» 

52 

33 

(C 

24 

u 

57 

u 

50 

It 

38 

It 

48 

It 

55 

It 

D. 


VALUE    OF   THE    BIRMINGHAM    GAUGES. 


Number. 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 


Size  in  inches. 
0.340 
.300 
.284 
.259 
.238 
.220 
.203 
.180 
.105 
.148 


466  APPENDIX. 


Number.  Size  in  inches. 

10  .134 

11  .         .120 

12  .100 

13  .095 

14  .083 

15  .072 

16  .065 

17  .058 

18  .049 

19  .042 

20  .035 

21  .032 

22  .028 

23  .025 

24  .022 

25  .020 

26  .018 

27  .016 

28  '       .014 

29  .013 

30  .012 


E. 

LOCOMOTIVE    BOILERS. 

If  the  ideas  of  Clark  and  Overman  are  correct,  the  value  of  verti 
cal  flues  with  the  water  inside,  as  compared  with  horizontal  flues 
with  water  outside,  is  comparatively  as  follows :  One  half  of  the  sur 
face  of  the  horizontal  tube  (the  upper  half)  is  available,  but  this 
half  generates  steam  twice  as  fast  as  the  same  area  of  upright  tube 
surface.  Thus  the  amount  of  evaporation  will  be  the  same  in  either 
position,  for  the  same  absolute  tube  surface,  not  considering  the  in 
creased  diameter  by  applying  the  heat  to  the  outside,  or  the  advan 
tage,  so  highly  estimated  by  Overman,  of  applying  the  heat  to  the 
convex  surface. 


APPENDIX.  467 

The  following  application  of  Montgomery's  vertical  flue  boiler  to 
the  locomotive  engine  for  heat  generation  and  application,  seems  to 
satisfy  nearly  all  requirements.  Retaining  the  original  furnace  shell, 
produce  it  forwards  so  that  it  shall  just  clear  the  driving  axle,  let 
the  sides  drop  to  within  two  feet  of  the  rail,  and  close  up  the  bottom. 
Next,  inside  of  this  place  a  rectangular  box  which  shall  be  a  con 
tinuation  of  the  inner  box,  the  top  being  about  nine  inches  above 
the  diametric  chord  of  the  semicircular  crown,  leaving  a  water  space 
of  three  or  four  inches  between  the  sides  and  bottom  of  the  two 
boxes.  Fill  the  inner  box  with  vertical  tubes,  the  top  and  bottom 
being  flue  plates,  the  tubes  being  screwed  in  at  one  end  and  fitted 
with  a  screw  thimble  at  the  other,  may  be  removed  for  cleaning  at 
any  time  and  will  effectually  stay  the  inner  box  against  the  enor 
mous  pressure  upon  the  top  and  bottom.  The  pressure  being  inside 
of  the  tubes  will  tend  to  keep  the  end  joints  tight,  where,  in  the 
common  boiler,  the  reverse  is  the  case. 

That  the  burning  gases  may  retain  sufficient  heat  to  burn  until 
they  are  discharged,  there  should  be  less  tube  surface  at  the  back 
than  at  the  front  end,  a  requirement  which  is  easily  satisfied  by  de 
creasing  the  number  and  increasing  the  size  of  tubes  from  the  front 
to  the  back  end.  In  the  common  boiler  the  ferrule  area  being  less 
than  the  flue  area,  a  stronger  blast  is  used  than  is  really  necessary 
to  draw  the  hot  gases  through  the  tubes,  while  in  the  vertical  tube 
boiler  the  gas  area  may  be  equally  large  at  all  points. 

Again,  any  amount  of  oxygen  may  be  applied  to  the  gases  at  any 
point  of  their  passage  from  the  furnace  to  the  smoke  box,  by  the 
admission  of  fresh  air  to  any  part  of  the  barrel.  Thus  the  advan 
tage  of  a  combustion  chamber  (if  there  is  any)  is  obtained  without 
the  sacrifice  of  a  single  inch  of  heating  surface,  as  we  only  require 
to  admit  air  between  the  tubes  and  not  into  them ;  this  may  be  done 
either  by  hollow  stay  bolts  or  by  larger  openings,  to  be  open  or  shut 
at  pleasure. 

If  the  gases  in  passing  through  the  boiler  are  left  to  themselves, 
we  get,  without  an  effort,  the  effect  produced  by  Montgomery's  third 
claim,  namely,  the  application  of  the  heat  to  the  upper  half  of  the 
tubes ;  and,  however  we  wish  to  apply  the  passing  heat  to  the  flues, 


468  APPENDIX. 

complete  control  over  the  motion  of  the  gases  may  be  had  by  the 
use  of  a  Venetian  blind  damper  in  the  smoke  box,  in  two  parts ;  the 
upper  and  the  lower  parts  moving  independently,  allow  us  to  throw 
the  heat  upon  any  part  of  the  length  of  the  tubes.  Of  course,  by 
heating  most  the  upper  part  of  the  flues,  we  stand  a  better  chance 
of  getting  circulation. 

It  might  be  objected  that  so  much  flat  boiler  surface  would  give  a 
form  more  liable  to  explosion  than  the  circular  barrel.  Experiments 
lately  made  by  William  Fairbairn,  (England,)  induced  by  the  burst 
ing  of  a  locomotive  fire  box,  show  that  the  flat  surfaces  are  the 
strongest  forms  of  the  boiler,  or,  to  use  his  own  words,  "  are  conclu 
sive  as  to  the  superior  strength  of  flat  surfaces  as  compared  with  the 
top,  or  even  the  cylindrical  parts  of  the  boiler."  His  experi 
ments  show  that  two  plates  one  fourth  and  three  eighths  inch  thick, 
connected  by  screw  stay  bolts  four  inches  from  centre  to  centre,  will 
resist  over  one  thousand  Ibs.  per  square  inch. 

By  such  a  plan  of  engine  we  may  always  have  any  amount  of 
heating  surface  with  a  moderate  sized  boiler,  and  a  low  centre  of 
gravity. 

The  excess  of  cost  of  the  engine,  above  described,  over  the  com 
mon  form  would  be  about  $500,  the  annual  interest  of  which  is  $30, 
which  must  be  saved  by  the  new  plan,  (say  ten  cords  of  wood). 
Any  saving  beyond  this  is  pure  gain. 


F. 

EFFECT    OF    GRADES    ON   THE    COST    OF    WORKING   RAILROADS. 

The  cost  of  working  a  railroad  will  be  increased  by  augmenting 
the  steepness  of  grades.  First,  because  of  the  mechanical  effect  of 
the  inclines ;  second,  on  account  of  decreased  capacity  of  the  road. 
The  cost  of  maintaining  and  working  a  road  consists  of  items,  a 
few  of  which  are  fractions  of  grades  and  many  which  are  not.  The 
chief  items  which  are  affected  by  grades  are,  fuel  consumption,  first 
cost  of  locomotives,  and  perhaps  wear  of  rails,  where  grades  are  so 


APPENDIX.  469 

steep  as  to  require  sand  ascending,  and  application  of  brakes  de 
scending,  the  rails  will  be  somewhat  more  worn.  When  not  so 
steep  as  this  the  repair  of  superstructure  will  not  be  much  increased. 
Steeper  inclines  involve  the  use  of  heavier  engines,  or  more  of  them. 
Heavy  engines  generally  have  no  more  weight  on  one  pair  of  wheels, 
and  often  not  so  much,  as  lighter  ones  ;  and  though  there  is  more  abra 
sive  power  on  increased  total  rolling  weight,  there  is  less  deflection 
of  rails,  by  means  of  less  concentrated  loads.  It  would  seem,  there 
fore,  that  the  effect  of  grades  upon  the  wear  of  superstructure  was 
but  little,  if  not  inconsiderable.  The  first  cost  of  engines  may  be 
increased  from  $1,000  to  $2,500  to  enable  them  to  work  steep 
grades.  If  the  wheels  are  the  same  size  in  both  engines,  we  should 
require  greater  steam  pressure,  consequently  (see  Chapter  XIV.) 
more  fuel ;  and  if  the  steam  power  was  the  same,  smaller  wheels  or 
larger  cylinders,  also  requiring  (Chapter  XIV.)  more  fuel. 

In  doubling  the  work  done  by  the  engine  we  by  no  means  double 
the  amount  of  fuel  consumed,. (see  Chapter  XIV.,)  but  increase  it 
by  about  ninety  per  cent. 

The  division  of  expenses  upon  five  of  the  largest  English  rail 
roads  was  for 'a  certain  time  as  follows  :  — 

Salaries $6.83 

Way  and  works    ......  15.76 

Locomotives     ......  35.15 

Cars 38.14 

Sundries  3.69 


$100.00 

Percentage  for  engines      ....  35.00 

Upon  the  roads  of  Belgium, 

Salaries  .......  $5.47 

Way  and  works 26.62 

Locomotives     ......  49.96 

Cars 14.80 

Sundries           .         .  3.15 


$100.00 

Locomotive  percentage     ....     50.00 
40 


470  APPENDIX. 

Upon  the  railroads  of  New  York  State  (2,200  miles)  (State  En 
gineer's  Report,  1854), 

Salaries   . 

Way  and  works   ..... 

Locomotives     ...... 

Cars    .         .  '      .         .         . 

Sundries  ...... 

Locomotive  percentage     . 

Average  percentage  of  all  of  the  above  charged  to  locomotives 
41f  of  the  whole  locomotive  expense ;  fuel  absorbs  62J  per  cent. ; 
and  as  a  double  amount  of  work  requires  ninety  per  cent,  more  fuel, 
we  have,  as  the  cost  of  working  a  grade  causing  a  double  resistance 
(say  twenty-five  feet  per  mile),  T9^  of  -ffo  of  ^&,  or  very  nearly 
22  per  cent,  of  the  cost  of  working  the  train ;  to  which  add  Tl,j  more, 
interest  on  locomotive  capital,  and  we  have,  as  the  bad  effect  of  a 
twenty-five  feet  grade,  when 

C  =  locomotive  capital, 
D  =  annual  cost  of  working, 

i         £  22 

rorfio5°r+I6oI)- 

'  Example. 


Locomotive  capital 

$1,000,000 

Cost  of  working 

200,000 

Annual  expense  of  a  level  road  (at  six  per  cent.) 

.     $60,000 

+  200,000 

$260,000 

And  upon  a  road  with  continuous  25 

feet  grades  . 

$60,000 

-f  6,000 

+  200,000 

-f  200,000  XTVo>  °r       . 

• 

.      44,000 

Total                            .        ..        . 

.         .         . 

$310,000 

APPENDIX.  471 

or  120  per  cent,  of  the  cost  of  working  the  level  road,  the  increase 
being  twenty  per  cent.,  or  allowing  five  per  cent,  for  other  contin 
gencies,  twenty-five  per  cent. ;  also  the  increase  due  to  a  fifty  feet 
grade,  fifty  per  cent. ;  and  so  on  as  long  as  only  one  engine  is  re 
quired  to  draw  the  full  train,  (its  power  being  increased  by  varying 
its  dimensions).  When  the  train  has  to  be  broken  and  two  or  more 
engines  are  needed,  the  percentage  will  of  course  increase.  The 
point  at  which  the  train  ought  to  be  broken  may  be  found  easily, 
either  as  depending  upon  the  load  or  the  grade,  by  a  comparison  of 
working  expenses. 


G. 

SPECIFICATION  FOR  A  PASSENGER  LOCOMOTIVE  ENGINE   FOR  THE 
A.    AND    B.   RAILROAD. 

Requirement: 

Speed  20  miles  per  hour,  including  stops ;  fuel,  wood  ;  weight  of 
train  150  tons;  maximum  grade  60  feet  per  mile;  sharpest  curve 
3°  or  1,910  feet  radius;  rail  60  Ibs.  per  yard  on  ties  2  feet  from 
centre  to  centre. 

General  Plan  and  Dimensions. 

Outside  connections  ;  four  five  feet  driving  wheels  with  best  Ames's 
tire,  all  tires  being  flanged;  level  cylinders  15  inches  diameter  of 
bore  and  20  inch  stroke.  Centre-bearing  truck,  with  inside  and  out 
side  bearings,  and  Lightener  boxes.  Square  wrought  iron  frame 
well  braced,  4-30  inch  Whitney  and  Sons'  cast-iron  truck  wheels, 
spread  60  inches  centre  to  centre.  Lifting  link  motion  working 
through  rockers,  valves  described  hereafter.  Truck  supplied  with 
fore  and  aft  safety  chains,  and  safety  beams  beneath  axles.  Weight 
on  drivers  30,000  Ibs.,  on  truck  10,000  Ibs.  Tender  to  be  mounted 
on  two  trucks,  each  of  4—30  inch  Whitney  and  Sons'  wheels,  spread 
54  inches  from  centre  to  centre.  To  have  square  iron  frames  well 
braced  with  outside  Lightener  boxes;  tank  to  hold  1,600  gallons. 


472  APPENDIX. 

Detailed  Specifications. 

Boiler.  —  Grate  38  inches  wide,  54  inches  long,  surface  20"  above 
rail,  grate  bars  cast  solid  for  6  inches  of  the  front  end,  to  be  4  inches 
deep,  and  J  inch  thick,  placed  f  inch  apart  in  the  clear ;  lower  edges 
chamfered  on  each  side  by  a  chamfer  of  J  inch  deep  and  ^  inch 
wide ;  centre  of  grate  bars  to  be  supported  by  a  wrought  iron  bar 
1  inch  thick  and  4  inches  deep,  attached  as  in  drawing.  Fire 
box. —  Outer  sides  of  furnace  shell  51  inches  wide  by  62  inches 
long ;  crown  8  feet  above  rail,  to  be  made  of  f  inch  iron  plates  with 
a  16  inch  necking  of  angle  iron  to  carry  the  rear  dome;  corners  to 
be  joined  by  flanges  rounded  to  a  4  inch  radius.  The  crown  of  the 
shell  to  be  raised  9  inches  above  the  barrel  crown,  the  connection 
being  made  by  a  sloping  offset  20  inches  long  on  top.  End  plates 
lap  jointed  to  sides  and  top ;  the  seams  joining  the  fire-box  to  the 
waist,  to  be  double  riveted.  Furnace  to  be  made  of  \  inch  copper 
plates,  j  inch  at  tubes,  lap  jointed,  42  J  inches  wide,  and  51 J  inches 
long  inside ;  side  water  spaces  to  be  3  inches  clear  at  the  bottom, 
widening  (by  sloping  inwards  the  sides  of  the  furnace)  to  4  inches 
at  the  top  of  inner  box ;  front  spaces  4  inches,  rear  spaces  4  inches 
at  bottom  and  5  inches  at  top.  Doorway  made  with  a  wrought  iron 
ring  fastened  with  |-  inch  rivets,  door  of  ^  inch  plate  with  ^  inch 
shield.  Furnace  joined  to  shell  with  ^  inch  copper  stay  bolts, 
screwed  and  riveted  at  both  ends,  placed  41  inches  from  centre  to 
centre.  Eight  roof-ribs  laid  widthwise  of  the  crown  of  the  furnace, 
being  each  6  inches  deep  and  f  inch  thick,  double  welded  at  the 
ends  and  riveted  at  the  centre,  held  down  by  T  head  bolts  5  inches 
between  centres,  bars  to  be  raised  above  the  crown  sheet  by  §  inch 
thimbles.  Dome  opening,  neckling  to  be  made  of  angle  iron  which 
shall  be  connected  with  the  roof-ribs  by  4— Ig-  inch  stays,  connected 
and  placed  as  in  the  drawing.  The  back  and  tube  sheets  of  the 
furnace  are  flanged  over  on  top ;  the  crown  is  flanged  downwards 
on  the  sides,  but  not  on  the  back  and  front.  One  dome  is  placed  on 
the  crown  of  fire-box  shell  26  inches  diameter  and  24  inches  high; 
opening  of  dome  into  boiler  16  inches  diameter.  Lower  part  of 
dome  of  wrought,  top  of  cast-iron,  put  on  with  a  ground  joint. 


APPENDIX.  473 

Furnace  and  shell  to  be  connected  at  bottom  by  a  wrought  iron  bar 
3  inches  wide,  2J  inches  deep.  The  whole  boiler  to  be  thoroughly 
caulked  inside  and  out.  Barrel  of  J  inch  best  Philadelphia  stamped 
charcoal  iron,  44  inches  diameter  outside  of  main  crown  next  the 
fire-box,  and  43  inches  next  the  smoke  box  end,  10  feet  long  with 
3  inch  angle  irons  at  ends.  Front  dome  of  J  inch  plate  worked  in 
one  piece,  23  inches  diameter.  End  plates  of  boiler  stayed  with 
six  1  inch  rods,  cottered  into  blocks,  riveted  to  plates ;  barrel  plates 
riveted  with  j  inch  rivets,  and  1|  inch  pitch.  Smoke  box,  2'  4V  long, 
same  diameter  as  barrel,  of  ^  inch  plates  well  riveted,  bolted  to  the 
angle  iron  so  as  to  be  easily  removed  for  inside  repairs ;  front  tube 
sheet  f  inch.  Tubes,  140  two  inch  (outside)  diameter  No.  9  thick 
ness  at  fire  end,  No.  14  at  smoke  end  10  feet  long,  placed  J  inch 
apart.  The  smoke  box  end  of  tubes  to  be  closed  at  pleasure  by  a 
Venetian  blind  damper.  Chimney  of  J  inch  iron  outside,  diameter 
16  inches,  top  6'  6"  above  crown  of  barrel,  fitted  with  proper  stack, 
cone,  and  sparker.  Ash  pan  of  £  inch  plate  made  with  1^  inch 
angle  iron,  and  band  on  upper  edge,  fitted  with  doors  both  before 
and  behind,  7  inches  deep  and  riding  6  inches  clear  of  the  rail. 
Steam  pipes,  6  inch  pipes  of  No.  10  copper  running  the  whole 
length  of  the  boiler,  connected  at  the  domes  with  5  inch  cast-iron 
stand  pipes.  Cast-iron  branch  pipes  in  smoke  box  leading  to  valve 
chests,  5  inches  diameter.  Throttle  to  be  in  a  cast-iron  chest  in 
smoke  box,  as  shown  in  drawing,  having  an  area  at  least  as  large  as 
the  steam  port.  Changes  of  direction  in  pipes  to  be  made  by  curves 
and  not  by  angles.  Exhaust  pipe  of  No.  10  copper,  5  inches 
diameter  at  lower  end,  fitted  with  a  variable  blast  orifice,  ranging 
from  eight  to  four  square  inches  area,  to  be  inclosed  in  a  petticoat 
pipe.  9 

Cylinders,  15  inches  bore,  and  long  enough  for  a  20  inch  stroke, 
or  28  J  inches  from  outside  to  outside  of  ground  faces,  casting  J  inch 
thick,  covers  1J  inch  thick,  placed  level  and  firmly  bolted  to  main 
frame  and  to  horizontal  truss  brace,  as  shown  in  drawing ;  heads  to 
go  on  with  ground  joint.  Valve  seat  to  have  steam  ports  14  X  If 
inches  ;  exhaust  port  14  X  2J  inches;  outside  lap  of  valve  f  inch, 
inside  nothing ;  ^  inch  lead  on  4|  inch  throw  of  valve,  gradually 

40* 


474  APPENDIX. 

increasing  as  the  throw  is  reduced,  to  scant  T6g-.  Steam  chests  bolted 
to  a  level  face,  ground  joint  with  |  inch  bolts  pitched  4  inches. 

Valve  motion.  —  Shifting  link  with  lifting  shaft,  sector,  lever, 
rocker,  etc.,  of  the  most  approved  form  ;  four  solid  eccentrics  of  5^ 
inches  throw,  fastened  to  axle  by  four  square  ended  set  screws  press 
ing  hardened  steel  dies,  cut  with  sharp  grooves  on  their  ends, 
against  the  axle ;  the  friction  of  the  dies  against  the  axle  holding 
the  eccentric  in  place.  Eccentric  straps  of  cast-iron,  with  oil  caps 
cast  on,  and  grooved  out  inside  so  as  to  shut  over  the  eccentric  and 
exclude  dust.  Link  forged  solid  and  case  hardened,  17  inches  by 
2£  inches  inside  the  slot ;  thickness  of  iron  all  around  the  slot  1 J 
inches,  whole  lateral  thickness  2  inches.  Eccentric  rods  of  •£  iron 
3  inches  deep,  5J  feet  between  centres,  fastened  to  link  and  to 
eccentric,  as  shown  in  the  drawing.  Link  curved  to  a  radius  6  inches 
less  than  the  distance  between  the  centre  of  driving  axle  and  centre 
of  link  at  mid  gear.  The  links,  boxes,  stack,  etc.,  to  be  of  wrought 
iron,  case  hardened.  Pistons  with  one  outside  composition  ring  and 
two  circumferential  grooves  filled  with  Balbett  metal,  and  one  inside 

,  ring  of  wrought  iron ;  outside  ring  cut  obliquely  at  one  place  with  a 
small  wrought  iron  flap  on  each  edge  to  prevent  leakage  of  steam  at 
the  point  of  division.  Glands  of  piston  and  valve  rod  stuff  boxes 
of  cast-iron  with  tight  brass  or  composition  bushings. 

frame  forged  from  good  scrap  4  X  2  inches,  the  main  bar  being 
straight  from  end  to  end  with  pedestals  welded  on ;  the  rear  end 

'  piece  to  be  a  heavy  forged  foot  plate,  the  front  end  an  oak  beam 
?Xl4  inches  placed  on  the  flat  side.  All  the  pedestals  on  one  side 
having  adjustable  keys.  Flat  boiler  braces  averaging  4^  X  J  inches 
with  broad  palms  riveted  to  the  boiler ;  the  attachment  at  the  fur 
nace  to  be  made  by  the  Rogers  expansion  brace,  details  of  /he  frame 
as  in  the  drawing ;  frame  to  be  placed  true  wherever  needed  to  re 
ceive  the  working  parts  of  the  engine. 

Wheels,  axles,  and  springs.  —  Four  cast-iron  driving  wheels  tired 
with  best  flanged  Ames's  tires  2  inches  thick,  diameter  with  tire  five 
feet,  tires  to  be  turned  to  a  true  cone  of  .072  inches  per  wheel, 
wheels  to  be  truly  balanced.  Best  scrap  or  bloom  axles,  front  7  and 
rear  6  inches  in  diameter,  bearings  8  inches  long,  collars  of  cast- 


APPENDIX.  475 

iron  held  by  set  screws,  axles  to  be  cylindrical  and  not  smaller  at 
the  centre  than  at  the  end.  Four  springs  of  seventeen  steel  plates, 
each  4  X  f  X  40  inches ;  equalizing  lever  between  springs.  Inside 
bearing  springs  of  truck  hung  from  equalizer,  which  latter  bears 
upon  the  axle  boxes. 

Slides,  pumps,  connecting  rods,  etc.,  etc.  —  Slides,  flat  wrought 
iron  bars  3  X  li  inches,  case  hardened.  Cross  head  bearing  of  cast- 
iron  16  inches  long  and  2  inches  thick.  Pumps,  full  stroke  brass 
pumps  T56-  inch  thick  with  1J  inch  plungers,  ram  of  wrought  iron 
with  an  eye  fixed  on  cross  head  and  worked  by  it.  Waterways  in 
body  2  inches,  in  valves  1|  inches.  Three  ball  valves  with  2J  inch 
hollow  balls,  one  for  suction  and  two  for  delivery ;  pipes  J  inch  thick, 
2  inches  diameter,  suction  of  iron,  delivery  of  copper,  cock  of  brass 
on  delivery  pipe  worked  by  rod  at  cab.  Air  chamber  on  forcing 
side  of  pump  equal  to  capacity  of  barrel ;  on  suction  side  half  the 
same.  Flat  connecting  rods  forged  from  solid  piles  without  welds. 
Babbett  lined  boxes  upon  all  stub  ends.  Straps  held  on  each  by 
two  bolts,  one  key  to  each  bearing.  Safety-valves,  one  to  be  3^ 
inches  diameter,  placed  on  the  rear  dome,  and  one  forward,  4  inches 
diameter,  both  to  be  well  fitted  and  supplied  with  the  proper  beams 
and  spring  balances.  Barrel  to  be  covered  with  hair  felting  l  inch 
thick,  to  be  furnished  with  a  Russia  iron  jacket.  Cylinders  to  be 
protected  by  an  ^  inch  felt  coat  and  cased  in  brass. 

The  engine  to  have  all  the  usual  fixtures,  bell,  whistle,  gauges, 
heater,  pet,  blow-off,  and  other  cocks,  name  plates,  oil  cups,  sand 
box,  tools,  oil  cans,  etc.,  etc.  Pilot  to  be  5  feet  long,  of  flat  hori 
zontal  wooden  bars  2J  X  4  inches  with  a  heavy  centre  piece,  the 
whole  to  be  well  hung  and  firmly  braced.  Cab  to  be  neatly  built, 
with  a  projecting  cornice,  and  windows,  doors,  etc.,  to  be  furnished 
in  the  best  manner.  The  whole  engine  to  be  well  painted  and  var 
nished.  The  draw  bar  to  be  strongly  attached  to  the  frame  of  the 
engine  at  30  inches  above  the  rail,  and  connected  by  a  double  ellip 
tical  spring  to  the  centre  beam  of  the  tender. 

Tender.  —  Tank  to  hold  1,GOO  gallons,  top  and  side  plates  g-  inch, 
and  bottom  plate  J  inch  well  riveted  and  caulked  inside  and  out. 
Brakes  to  apply  from  a  single  wheel  to  each  side  of  all  of  the 


476  APPENDIX. 

• 
wheels,  that  is,  at  sixteen  points ;   brake  blocks  hung  with  safety 

chains  and  springs  to  carry  them  away  from  the  wheels.  One 
spring  26  inches  long,  often  levers  3  X  -finches  over  each  wheel. 
Frame  of  seasoned  oak  10  X  4  inches,  centre  beam  5  X  20  inches. 
The  whole  to  be  thoroughly  painted  and  varnished. 

General  Provision. 

All  of  the  material,  both  of  engine  and  tender,  to  be  of  the  very 
best  quality,  and  all  of  the  construction  done  in  the  most  thorough 
and  workmanlike  manner.  The  engine  and  tender  being  in  every 
respect  equal  to  the  best  that  has  heretofore  been  sent  from  the 
—  shops.  For  more  detailed  information,  see  plans  accompany 
ing. 


II. 


RELATIVE    COST    OF     TRANSPORT     BY   RAILROAD    AND     BY    STAGE. 

Too  great  a  reduction  of  the  cost  of  travel  was  both  expected  of 
and  given  by  railroad  companies  at  the  commencement  of  the  sys 
tem,  as  the  following  will  show  :  — 

Voted,  "That  the  directors  are  hereby  earnestly  and  urgently 
requested  forthwith  to  increase  the  rates  of  transportation,  both  for 
passengers  and  freight,  in  all  cases  in  which,  in  their  opinion,  they 
are  now  too  low,  and  hereafter  to  decline  all  business  that  will  not 
give  to  the  corporation  a  full  remuneration  for  expenses  and  a  fair 
profit  for  its  transportation." 

Why  the  railroad  rates  should  have  been  placed  so  low,  it  would 
be  hard  to  show. 

The  cost  of  moving  eight  passengers  by  stage  one  hundred  miles, 
would  be  somewhat  as  follows.  Let  a  common  road  cost  one  thou 
sand  dollars  per  mile,  and  suppose  the  stage  travel  to  use  one  tenth 
of  the  capital  expended ;  the  daily  interest  for  one  trip  is 


APPENDIX.  477 

.     $1.64 


Ten  horses  and  one  stage, 

'  1000  +  500 


_ 
obo 

Daily  salary  of  driver  and  stable  hands,      ....       5.00 
Daily  interest  on  stable  cost,  repairs,  &c.,  &c.,         .         .  1.03 

Whole  cost  of  moving  8  passengers  1  00  miles,     .         .         .     $8.00 
Cost  of  moving  one  passenger  one  mile,  .         .         .  .01 

Again.  Let  a  railroad  cost  $25,000  per  mile,  one  hundred  miles 
cost  $2,500,000,  and  if  we  run  ten  trains  per  day  the  daily  interest, 
at  six  per  cent.,  for  one  train  is 


2500000  XTfe  .  10 
~865~ 


A  locomotive  costs  $10,000, 
Two  cars  cost  4,000, 


,30 


And  the  daily  cost  of  road  and  equipment,         .         .         .     $43.40 
divide  by  100,  for  the  cent  per  mile,  .         .         .  0.43 

The  average  number  of  passengers  carried  in  one  car, 
(see  New  York  State  Engineer's  Report,)  is  17  ;  two 
cars,  34,  whence  ||  =  ......  1J  cents 

The  daily  cost  per  mile,  per  passenger,  is  then,  for  the  use 

of  the  road  and  equipment,    .....         1^       " 

The  cost  of  maintaining  and  working  is,  per  passenger, 
per  mile,  (see  New  York  State  Engineer's  Report  for 
1854,)  .  .  ;  ......  -,  1£  ". 

Whence  the  whole  cost  of  carrying  one  passenger  one 

mile  upon  a  railroad  will  be  ....         2^      " 

The  relative  cost  of  transport  is,  then,  thus, 

By  stage,     .         .         .         .         .         .         1      cent 

By  railroad,     ......     2T75    " 


478  APPENDIX. 

and  the  relative  charge  thus, 

By  stage,        .         .         .         .         .         .5  cents 

By  railroad,       .         .         .         .         .         .     3      " 

And  the  comparative  profit  as  5  less  1,  or  4 ;  to*  3  less  2T72,  or 
or  as  1  to  9.6. 


I. 


FORM    FOR    RECORDING    THE    RESULTS     OF    EXPERIMENTAL    TRIPS 
WITH    LOCOMOTIVES. 

In  comparing  the  work  done  by  different  locomotives,  we  must 
know  not  only  the  relative  amounts  of  material  consumed,  but  also 
tlie  exact  nature  of  the  work  done,  as  depending  upon  speed,  load, 
curves,  and  grades.  The  following  blank,  when  filled,  has  been 
found  to  give  complete  information,  for  comparison. 


Station,          .... 

Time  of  arriving, 

Time  of  departing, 

Time  running, 

Time  standing,      .         .         . 

Distance,  ..... 

Rise, 

Fall, 

Degrees  of  curvature,    . 

Equated  distance, 

Cars  taken,  .... 

Cars  left, 

Load  between  stations, 

Equated  mileage  of  train, 

Gauge  pressure,     . 

Notch  of  sector, 

Fuel  used,     .... 

Water  used,      .... 

Lbs.  of  fuel  per  gallon  of  water, 


APPENDIX.  479 


Lbs.  of  fuel  per  equated  mileage,  per  ton  or  per  passenger, 
Comparative  effect,  .  .  .     '    .        ,.       ,.      '  . 


K. 


PROPER  WEIGHT  OF  LOCOMOTIVES. 

To  move  a  given  load  the  engine  requires  a  certain  amount  of 
power  ;  to  exert  such  power  there  is  needed  load  enough  on  the 
drivers  to  prevent  slipping  on  the  rail.  This  load  varies  from  three 
times  the  tractive  power,  (in  the  best  state  of  the  rails,)  to  ten  times 
the  tractive  power,  and  even  more,  (in  the  worst  state).  A  fair 
working  average  (without  sand),  being  one  sixth,  with  much  less. 
Sand  must  be  used  upon  grades  and  upon  bad  rails.  To  find  then 
the  proper  weight,  we  have  only  to  estimate  the  tractive  power  upon 
the  hardest  point  of  the  road,  and  multiply  it  by  six. 

Examples. 

How  heavy  an  engine  is  needed  to  draw  two  hundred  tons  (in 
cluding  engine  and  tender)  at  twenty  miles  per  hour  over  sixty 
feet  grades  ? 

The  resistance  on  a  level  is 


200  X    —  jj—  +  8   =  •         •         •         2>060  pounds. 
The  resistance  due  to  the    rade 


.         .         .     5,200  « 

The  resistance  due  to  curves 

200X5=         .....         1,000  " 

And  the  whole  resistance,  .         .         .         .               8,260  " 

Which  multiplied  by  6,  is        .         .         .         .       49,560  " 

or  22.1  tons,  to  which  add  5  tons  as  the  necessary  load  upon  the 


480  APPENDIX. 

truck,  and  the  whole  weight  is  27.1  tons,  which  is  the  necessary 
weight  of  an  engine  to  draw  200  tons  over  60  feet  grades,  at  20 
miles  per  hour. 
Or,  generally, 

Let  W=  Weight  of  engine,  tender,  and  train,  in  tons, 
«     V=  Speed  in  miles  per  hour, 

"    -         Fraction  expressing  the  grade, 

a 
"    c        Resistance,  in  pounds  per  ton  due  to  the  sharpest 

curve,  which,  assume  as  5  Ibs.,  as  we  have  no 

reliable  data, 

and  we  have,  as  the  weight  of  the  engine, 


2240 


weight  of  engine  exclusive  of  weight  on  truck. 

If  we  assume  the  adhesion  as  one  fourth  of  the  weight  on  the 
drivers,  and  load  150  tons,  speed  twenty  miles  per  hour,  and  grade 
forty  feet  per  mile,  the  above  formula  becomes, 


2240 

nine  tons  nearly. 

To  which  add  five  tons,  and  we  have  as  the  whole  weight,  four 


teen  tons. 


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